SUMF1 Research Articles

Bone marrow transplantation increases sulfatase activity in somatic tissues in a multiple sulfatase deficiency mouse model

BackgroundMultiple Sulfatase Deficiency (MSD) is an ultra-rare autosomal recessive disorder characterized by deficient enzymatic activity of all known sulfatases. MSD patients frequently carry two loss of function mutations in the SUMF1 gene, encoding a formylglycine-generating enzyme (FGE) that activates 17 different sulfatases. MSD patients show common features of other lysosomal diseases like mucopolysaccharidosis and metachromatic leukodystrophy, including neurologic impairments, developmental delay, and visceromegaly. There are currently no approved therapies for MSD patients. Hematopoietic stem cell transplant (HSCT) has been applied with success in the treatment of certain lysosomal diseases. In HSCT, donor-derived myeloid cells are a continuous source of active sulfatase enzymes that can be taken up by sulfatase-deficient host cells. Thus, HSCT could be a potential approach for the treatment of MSD.MethodsTo test this hypothesis, we used a clinically relevant mouse model for MSD, B6-Sumf1(S153P/S153P) mice, engrafted with bone marrow cells, Sumf1+/+, from B6-PtprcK302E mice (CD45.1 immunoreactive).ResultsAfter 10 months post-transplant, flow cytometric analysis shows an average of 90% of circulating leukocytes of donor origin (Sumf1(+/+)). Enzymatic activity for ARSA, ARSB, and SGSH is significantly increased in spleen of B6-Sumf1(S153P/S153P) recipient mice. In non-lymphoid organs, only liver and heart show a significant correction of sulfatase activity and GAG accumulation. Frequency of inflammatory cells and lysosomal pathology is significantly reduced in liver and heart, while no significant improvement is detected in brain.ConclusionsOur results indicate that HSCT could be a suitable approach to treat MSD-pathology affecting peripheral organs, however that benefit to CNS pathology might be limited.

Lysosomal storage diseases. Sphingolipidoses – leukodystrophy

Lysosomal storage diseases. Sphingolipidoses – leukodystrophy

Late infantile form of multiple sulfatase deficiency with a novel missense variant in the SUMF1 gene: case report and review

BackgroundMultiple sulfatase deficiency (MSD) is a rare lysosomal storage disorder caused due to pathogenic variants in the SUMF1 gene. The SUMF1 gene encodes for formylglycine generating enzyme (FGE) that is involved in the catalytic activation of the family of sulfatases. The affected patients present with a wide spectrum of clinical features including multi-organ involvement. To date, almost 140 cases of MSD have been reported worldwide, with only four cases reported from India. The present study describes two cases of late infantile form of MSD from India and the identification of a novel missense variant in the SUMF1 gene.Case presentationIn case 1, a male child presented to us at the age of 6 years. The remarkable presenting features included ichthyosis, presence of irritability, poor social response, thinning of corpus callosum on MRI and, speech regression. Clinical suspicion of MSD was confirmed by enzyme analysis of two sulfatase enzymes followed by gene sequencing. We identified a novel missense variant c.860A > T (p.Asn287Ile) in exon 7 of the SUMF1 gene. In case 2, a two and a half years male child presented with ichthyosis, leukodystrophy and facial dysmorphism. We performed an enzyme assay for two sulfatases, which showed significantly reduced activities thereby confirming MSD diagnosis.ConclusionOverall, present study has added to the existing data on MSD from India. Based on the computational analysis, the novel variant c.860A > T identified in this study is likely to be associated with a milder phenotype and prolonged survival.

Drug screening identifies tazarotene and bexarotene as therapeutic agents in multiple sulfatase deficiency

Multiple sulfatase deficiency (MSD, MIM #272200) results from pathogenic variants in the SUMF1 gene that impair proper function of the formylglycine‐generating enzyme (FGE). FGE is essential for the posttranslational activation of cellular sulfatases. MSD patients display reduced or absent sulfatase activities and, as a result, clinical signs of single sulfatase disorders in a unique combination. Up to date therapeutic options for MSD are limited and mostly palliative. We performed a screen of FDA‐approved drugs using immortalized MSD patient fibroblasts. Recovery of arylsulfatase A activity served as the primary readout. Subsequent analysis confirmed that treatment of primary MSD fibroblasts with tazarotene and bexarotene, two retinoids, led to a correction of MSD pathophysiology. Upon treatment, sulfatase activities increased in a dose‐ and time‐dependent manner, reduced glycosaminoglycan content decreased and lysosomal position and size normalized. Treatment of MSD patient derived induced pluripotent stem cells (iPSC) differentiated into neuronal progenitor cells (NPC) resulted in a positive treatment response. Tazarotene and bexarotene act to ultimately increase the stability of FGE variants. The results lay the basis for future research on the development of a first therapeutic option for MSD patients.

Unexpected Phenotype Reversion and Survival in a Zebrafish Model of Multiple Sulfatase Deficiency.

Multiple sulfatase deficiency (MSD) is a rare recessively inherited Mendelian disorder that manifests with developmental delay, neurodegeneration, skeletal deformities, facial dysmorphism, congenital growth retardation, and other clinical signs. The disorder is caused by mutations in the SUMF1 gene, which encodes the formylglycine-generating enzyme (FGE), and responsible for the activation of sulfatases. Mutations in SUMF1 result in reduced or absent FGE function with consequent compromised activities of its client sulfatases. This leads to an accumulation of enzyme substrates, such as glycosaminoglycans and sulfolipids, within lysosomes and subsequently impaired lysosome function and cellular pathology. Currently, there are no disease modifying therapeutic options for MSD patients, hence the need for more suitable animal models to investigate the disorder. Here, we describe the characterisation of a sumf1 null zebrafish model, which has negligible sulfatase activity. Our sumf1 −/− zebrafish model successfully recapitulates the pathology of MSD such as cranial malformation, altered bone development, an enlarged population of microglia, and growth retardation during early development but lacks early lethality of mouse Sumf1 −/− models. Notably, we provide evidence of recovery in MSD pathology during later developmental stages, resulting in homozygous mutants that are viable. Hence, our data suggest the possibility of a unique compensatory mechanism that allows the sumf1 −/− null zebrafish to survive better than human MSD patients and mouse Sumf1 −/− models.

Single-nucleotide polymorphisms in the sulfatase-modifying factor 1 gene are associated with lung function and COPD.

Single nucleotide polymorphisms (SNPs) in various genes have been shown to associate with COPD, suggesting a role in disease pathogenesis. Sulfatase modifying factor (SUMF1) is a key modifier in connective tissue remodelling, and we have shown previously that several SNPs in SUMF1 are associated with COPD. The aim of this study was to investigate the association between SUMF1 SNPs and advanced lung function characteristics.Never-, former and current smokers with (n=154) or without (n=405) COPD were genotyped for 21 SNPs in SUMF1 and underwent spirometry, body plethysmography, diffusing capacity of the lung for carbon monoxide (DLCO) measurement and impulse oscillometry.Four SNPs (rs793391, rs12634248, rs2819590 and rs304092) showed a significantly decreased odds ratio of having COPD when heterozygous for the variance allele, together with a lower forced expiratory volume in 1 s (FEV1) and FEV1/forced vital capacity (FVC) ratio and an impaired peripheral resistance and reactance. Moreover, individuals homozygous for the variance allele of rs3864051 exhibited a strong association to COPD, a lower FEV1/FVC, FEV1 and DLCO, and an impaired peripheral resistance and reactance. Other SNPs (rs4685744, rs2819562, rs2819561 and rs11915920) were instead associated with impaired lung volumes and exhibited a lower FVC, total lung capacity and alveolar volume, in individuals having the variance allele.Several SNPs in the SUMF1 gene are shown to be associated with COPD and impaired lung function. These genetic variants of SUMF1 may cause a deficient sulfation balance in the extracellular matrix of the lung tissue, thereby contributing to the development of COPD.

Natural disease history and characterization of SUMF1 molecular defects in multiple sulfatase deficiency: a case report

Multiple sulfatase deficiency (MSD) is a very rare lysosomal storage disease(LSD) caused by mutations in the SUMF1 gene. So far, about 143 patients with MSD have been reported in previous studies, although this figure is likely an underestimation due to under-reporting and under-recognition. This report showed the genetic and clinical aspects of a patient with MSD compared with previously reported patients.

A systematic review and meta-analysis of published cases reveals the natural disease history in multiple sulfatase deficiency.

Multiple Sulfatase Deficiency (MSD, MIM#272200) is an ultra-rare lysosomal storage disorder arising from mutations in the SUMF1 gene, which encodes the formylglycine-generating enzyme (FGE). FGE is necessary for the activation of sulfatases, a family of enzymes that are involved in the degradation of sulfated substrates such as glycosaminoglycans and sulfolipids. SUMF1 mutations lead to functionally impaired FGE and individuals with MSD demonstrate clinical signs of single sulfatase deficiencies, including metachromatic leukodystrophy (MLD) and several mucopolysaccharidosis (MPS) subtypes. Comprehensive information related to the natural history of MSD is missing. We completed a systematic literature review and a meta-analysis on data from published cases reporting on MSD. As available from these reports, we extracted clinical, genetic, biochemical, and brain imaging information. We identified 75 publications with data on 143 MSD patients with a total of 53 unique SUMF1 mutations. The mean survival was 13 years (95% CI 9.8-16.2 years). Seventy-five clinical signs and 11 key clusters of signs were identified. The most frequently affected organs systems were the nervous, skeletal, and integumentary systems. The most frequent MRI features were abnormal myelination and cerebral atrophy. Individuals with later onset MSD signs and survived longer than those with signs at birth. Less severe mutations, low disease burden and achievement of independent walking positively correlated with longer survival. Despite the limitations of our approach, we were able to define clinical characteristics and disease outcomes in MSD. This work will provide the foundation of natural disease history data needed for future clinical trial design.

A systematic cross-sectional survey of multiple sulfatase deficiency

Multiple Sulfatase Deficiency (MSD) is an inborn error of metabolism caused by pathogenic variants in the SUMF1 gene encoding the formylglycine-generating enzyme (FGE) that activates all known sulfatases. FGE deficiency results in widespread tissue accumulation of multiple sulphated substrates.Through a systematic analysis of published cases, we retrieved 80 MSD cases and reviewed the disease clinical, biochemical, and genetic findings. Leukodystrophy, neurosensorial hearing loss, and ichthyosis were the most frequent findings at diagnosis. Of 51 reported pathogenic variants, 20 were likely gene disruptive and the remaining were missense variants. No correlations between class of variants and clinical severity or degree of enzyme deficiency were detected. However, cases harboring variants located at N-terminal always had severe neonatal presentations. Moreover, cases with neonatal onset showed the lowest overall survival rate compared to late-infantile and juvenile onsets. Using GnomAD, carrier frequency for pathogenic SUMF1 variants was estimated to be ~1/700 and the disease prevalence was approximately 1/2,000,000.In summary, MSD is an ultra-rare multisystem disorder with mainly neurologic, hearing and skin involvements. Although the collected data were retrospective and heterogenous, the quantitative data inform the disease natural history and are important for both counseling and design of future interventional studies.

Nonlinear magnetoelectric effects in flexible composite ferromagnetic – Piezopolymer structures

Nonlinear magnetoelectric (ME) effects in a flexible composite planar structure, containing mechanically coupled layers of amorphous FeBSiC ferromagnet and PVDF piezoelectric polymer have been experimentally investigated. Under the action of a weak harmonic magnetic field h with frequency f=50–1000Hz and tangential bias magnetic field H=1–80Oe, the structure generated a voltage of the same frequency. The efficiency of linear ME conversion reached 3.4V/(cm·Oe) for the optimum bias field Hm≈15Oe. On increasing the excitation field up to h ∼7Oe, the structure generated second and third harmonics with efficiencies of ∼25mV/(cm·Oe2) and ∼2.5mV/(cm·Oe3), respectively. The amplitudes of the harmonics were not monotonous functions on the bias field H and grew with the increase in the alternating field h. Under the action of two alternating fields with different frequencies f1 and f2, the structure generated ac voltages with frequencies equal to the sum and difference frequencies f1±f2. The efficiency of magnetic fields mixing reached a maximum of ∼30mV/(cm·Oe2) in the absence of the bias field. The effects of harmonics generation and magnetic fields mixing arise due to the nonlinear dependence of the ferromagnet’s magnetostriction λ on the bias field H. The efficiency of the nonlinear processes is proportional to the derivatives of the magnetostriction over magnetic field. The nonlinear ME effects in the ferromagnet-piezopolymer flexible structures can be used to design high-sensitivity dual ac/dc magnetic field sensors and energy harvesting devices.

Sulfatase modifying factor 1 trafficking through the cells: from endoplasmic reticulum to the endoplasmic reticulum.

Sulfatase modifying factor 1 (SUMF1) is the gene mutated in multiple sulfatase deficiency (MSD) that encodes the formylglycine-generating enzyme, an essential activator of all the sulfatases. SUMF1 is a glycosylated enzyme that is resident in the endoplasmic reticulum (ER), although it is also secreted. Here, we demonstrate that upon secretion, SUMF1 can be taken up from the medium by several cell lines. Furthermore, the in vivo engineering of mice liver to produce SUMF1 shows its secretion into the blood serum and its uptake into different tissues. Additionally, we show that non-glycosylated forms of SUMF1 can still be secreted, while only the glycosylated SUMF1 enters cells, via a receptor-mediated mechanism. Surprisingly, following its uptake, SUMF1 shuttles from the plasma membrane to the ER, a route that has to date only been well characterized for some of the toxins. Remarkably, once taken up and relocalized into the ER, SUMF1 is still active, enhancing the sulfatase activities in both cultured cells and mice tissues.

Natural disease history and characterisation of SUMF1 molecular defects in ten unrelated patients with multiple sulfatase deficiency.

BackgroundMultiple sulfatase deficiency is a rare inherited metabolic disorder caused by mutations in the SUMF1 gene. The disease remains poorly known, often leading to a late diagnosis. This study aimed to provide improved knowledge of the disease, through complete clinical, biochemical, and molecular descriptions of a cohort of unrelated patients. The main objective was to identify prognostic markers, both phenotypic and genotypic, to accelerate the diagnosis and improve patient care.MethodsThe phenotypes of ten unrelated patients were fully documented at the clinical and biochemical levels. The long-term follow-up of each patient allowed correlations of the phenotypes to the disease outcomes. Each patient’s molecular defects were also identified. Site-directed mutagenesis was used to individually express the mutants and assess their stability. Characterisation of the protein mutants was completed by in silico analyses based on sequence comparisons and structural models.ResultsThe most severe cases were characterised by the presence of non-neurological symptoms as well as the occurrence of psychomotor regression before 2 years of age. Nine novel SUMF1 mutations were identified. Clinically severe forms were often associated with SUMF1 mutations that strongly affected the protein stability and/or catalytic function as predicted from in silico and western blot analyses.ConclusionsThis detailed clinical description and follow-up of a cohort of patients, together with the molecular characterisation of their underlying defects, contribute to improved knowledge of multiple sulfatase deficiency. Predictors of a bad prognosis were the presence of several non-neurological symptoms and the onset of psychomotor regression before 2 years of age. No strict correlation existed between in vitro residual sulfatase activity and disease severity. Genotype–phenotype correlations related to previously reported mutants were strengthened. These and previous observations allow not only improved prediction of the disease outcome but also provision of appropriate care for patients, in the expectation of specific treatment development.Electronic supplementary materialThe online version of this article (doi:10.1186/s13023-015-0244-7) contains supplementary material, which is available to authorized users.

Clinical characterization and mutation identification for multiple sulfatase deficiency patients in China

Multiple sulfatase deficiency is a rare autosomal recessively inherited lysosomal storage disorder characterized by the accumulation of sulfated lipids and acid mucopolysaccharides. The aim of this study was to explore the clinical manifestations, enzyme activities and SUMF1 gene mutations in two Chinese patients with multiple sulfatase deficiency. One boy and one girl from two families were studied. Both patients presented with mental retardation, mild coarse facial features, a neurodegenerative course of disease with loss of sensory and motor function after 2 years of age, ichthyosis and skeletal abnormalities (kyphosis or/and scoliosis). Clinical characteristics indicate multiple sulfatase deficiency.Sulfatases activities in blood leucocytes, plasma or cultured fibroblast of the patients were measured.Genomic DNAs were extracted from peripheral blood leukocytes from the patients and their parents. All SUMF1 gene exons and intron-exon boundaries were amplified by PCR and subjected for direct sequencing. In case 1, five sulfatases activities of blood leucocytes and four sulfatases of cultured skin-fibroblasts were analyzed.In case 2, three sulfatases activities of blood leucocytes were tested.Significantly decreased sulfatases activities confirmed the diagnosis of multiple sulfatase deficiency.On SUMF1 gene, c.793_794 insATG (p. P265X)/ c.1045C>T (p.R349W) in case 1 and c.451A>G (p.K151E)/ c.1046G>C (p.R349Q) in case 2 were detected, respectively. Three novel mutations c.793_794insAGT, c.1046G>C and c.451A>G were identified. Multiple sulfatase deficiency usually results in multi-organ damage, especially neurologic, skeletal and skin.Sulfatases assay and SUMF1 gene analysis are necessary for the diagnosis. Two Chinese cases with multiple sulfatase deficiency were firstly reported. Three novel mutations were found.It should be considered that the mutation profile of SUMF1 gene in Chinese patients is different from other populations.

Rapid degradation of an active formylglycine generating enzyme variant leads to a late infantile severe form of multiple sulfatase deficiency

Multiple sulfatase deficiency (MSD) is a rare inborn error of metabolism affecting posttranslational activation of sulfatases by the formylglycine generating enzyme (FGE). Due to mutations in the encoding SUMF1 gene, FGE's catalytic capacity is impaired resulting in reduced cellular sulfatase activities. Both, FGE protein stability and residual activity determine disease severity and have previously been correlated with the clinical MSD phenotype. Here, we report a patient with a late infantile severe course of disease. The patient is compound heterozygous for two so far undescribed SUMF1 mutations, c.156delC (p.C52fsX57) and c.390A>T (p.E130D). In patient fibroblasts, mRNA of the frameshift allele is undetectable. In contrast, the allele encoding FGE-E130D is expressed. FGE-E130D correctly localizes to the endoplasmic reticulum and has a very high residual molecular activity in vitro (55% of wildtype FGE); however, it is rapidly degraded. Thus, despite substantial residual enzyme activity, protein instability determines disease severity, which highlights that potential MSD treatment approaches should target protein folding and stabilization mechanisms.

On the uniqueness of periodic decomposition

Consider arbitrary nonzero real numbers a1;:::;ak. An (a1;:::;ak)-decomposition of a function f : R! R is a sum f1 + +fk = f where fi : R! R is an ai-periodic function. Such a decomposition is not unique because there are several solutions of the equation h1 + + hk = 0 (hi : R! R is ai-periodic). We will give solutions of this equation with a certain simple structure (trivial solutions) and study whether there exist other solutions or not. If not, we say that the (a1;:::;ak)-decomposition is essentially unique. We characterize those periods for which essentially uniqueness holds.

NECESSARY OPTIMALITY CONDITIONS FOR SUPER MINIMIZERS IN STRUCTURAL PROBLEMS OF MULTIOBJECTIVE OPTIMIZATION

The primary goal of this paper is to study the so-called super minimizers of the sum F1 + F2 related to the concept of super efficiency in constrained problems of multiobjective optimization, where each cost mapping Fi is generally set-valued for i = 1, 2. We will derive necessary conditions (of the subdifferential type) for super minimizers of the sum F1 + F2 on the basis of advanced tools of variational analysis and generalized differentiation that are new in both finite-dimensional and infinite-dimensional settings for problems with single-valued and set-valued objectives.

113. Combining Brain and Systemic Injections of SUMF1 Gene by AAV2/9-Mediated Delivery Results in Re-Activation of Sulfatases in a Mouse Model of Multiple Sulfatase Deficiency (MSD)

113. Combining Brain and Systemic Injections of SUMF1 Gene by AAV2/9-Mediated Delivery Results in Re-Activation of Sulfatases in a Mouse Model of Multiple Sulfatase Deficiency (MSD)

The Non-catalytic N-terminal Extension of Formylglycine-generating Enzyme Is Required for Its Biological Activity and Retention in the Endoplasmic Reticulum

Formylglycine-generating enzyme (FGE) catalyzes the oxidation of a specific cysteine residue in nascent sulfatase polypeptides to formylglycine (FGly). This FGly is part of the active site of all sulfatases and is required for their catalytic activity. Here we demonstrate that residues 34-68 constitute an N-terminal extension of the FGE catalytic core that is dispensable for in vitro enzymatic activity of FGE but is required for its in vivo activity in the endoplasmic reticulum (ER), i.e. for generation of FGly residues in nascent sulfatases. In addition, this extension is needed for the retention of FGE in the ER. Fusing a KDEL retention signal to the C terminus of FGE is sufficient to mediate retention of an N-terminally truncated FGE but not sufficient to restore its biological activity. Fusion of FGE residues 1-88 to secretory proteins resulted in ER retention of the fusion protein. Moreover, when fused to the paralog of FGE (pFGE), which itself lacks FGly-generating activity, the FGE extension (residues 34-88) of this hybrid construct led to partial restoration of the biological activity of co-expressed N-terminally truncated FGE. Within the FGE N-terminal extension cysteine 52 is critical for the biological activity. We postulate that this N-terminal region of FGE mediates the interaction with an ER component to be identified and that this interaction is required for both the generation of FGly residues in nascent sulfatase polypeptides and for retention of FGE in the ER.

Multiple sulfatase deficiency in a Turkish family resulting from a novel mutation

Multiple sulfatase deficiency (MSD) is an inherited lysosomal storage disease that affects post-translational activation of all of the sulfatases. Since biochemical and clinical findings are variable, the diagnosis is difficult in most of the cases. Missense, nonsense, microdeletion and splicing mutations in SUMF1 gene were found in all of the MSD patients analyzed. Here, we present clinical findings of two consanguineous patients with multiple sulfatase deficiency. They were found to be homozygous for a novel missense mutation c.739G > C causing a p.G247R amino acid substitution in the SUMF1 protein.

Serial magnetic resonance imaging and neurophysiological studies in multiple sulphatase deficiency

We present serial clinical, magnetic resonance imaging (MRI) and neurophysiological findings of a patient with multiple sulphatase deficiency (MSD), who was first admitted at the age of 9 months, because of psychomotor retardation. MRI demonstrated extensive diffuse symmetrical high signal in the deep white matter of both cerebral hemispheres, as well as of the subcortical white matter and the brainstem, while there was additional enlargement of sulci and subdural spaces and mild atrophy. Assay of arylsulphatase A activity in white blood cell homogenates at the age of 29 months disclosed a marked deficiency of the enzyme, compatible with the diagnosis of early-infantile metachromatic leukodystrophy. During the course of a later admission, the presence of ichthyosis pointed out to the possible diagnosis of MSD; further assays of sulphatases in plasma, leukocytes as well as in cultured fibroblasts, combined with an abnormal excretion of mucopolysaccharides and sulphatides in urine confirmed the diagnosis. Molecular analysis identified a homozygous disease-causing mutation (R349W) of the SUMF1 gene. Serial neurophysiological and MRI studies demonstrated the progressive nature of the disorder (regarding both central and peripheral nervous system), correlating with the clinical deterioration (spastic quadriplegia, optic atrophy and epilepsy) with subsequent death at the age of 4 years.