WITHDRAWN: Physiological roles of steroid sulfatase. A minireview.
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Journal Article↗
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Qualitative and quantitative differences in sulfatase A which distinguish different forms of classical metachromatic leukodystrophy (MLD).
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Adolescent↗
Chondroitin sulfatase--producing and hyaluronidase--producing oral bacteria associated with periodontal disease.
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Adult↗
Mucopolysaccharidosis IVA: four new exonic mutations in patients with N-acetylgalactosamine-6-sulfate sulfatase deficiency.
We report four new mutations in Japanese patients with mucopolysaccharidosis IVA (MPSIVA) who were heterozygous for a common double gene deletion. A nonsense mutation of CAG to TAG at codon 148 in exon 4 was identified, resulting in a change of Q to a stop codon and three missense mutations. V (GTC) to A (GCC) at codon 138 in exon 4, P (CCC) to S (TCC) at codon 151 in exon 5, and P (CCC) to L (CTC) at codon 151 in exon 5. Introduction of these mutations into the normal GALNS cDNA and transient expression in cultured fibroblasts resulted in a significant decrease in the enzyme activity. V138A and Q148X mutations result in changes of restriction site, which were analyzed by restriction-enzyme assay. P151S and P151L mutations that did not alter the restriction site were detected by direct sequencing or allele specific oligohybridization. Detection of the double gene deletion was initially done using Southern blots and was confirmed by PCR. Haplotypes were determined using seven polymorphisms to the GALNS locus in families with the double gene deletion. Haplotype analysis showed that the common double gene deletion occurred on a single haplotype, except for some variation in a VNTR-like polymorphism. This finding is consistent with a common founder for all individuals with this mutation.
Adolescent↗
The hydrolysis of estrone sulfate and dehydroepiandrosterone sulfate by MCF-7 human breast cancer cells.
Reports of estrone (E1) and dehydroepiandrosterone (DHEA) sulfatase (sulfohydrolase) activities within many human breast cancers have prompted us to undertake the identification and partial characterization of these enzyme activities within MCF-7 human breast cancer cells. Enzyme assays were performed within subcellular preparations and intact cultures by quantifying the total nonpolar 3H-labeled metabolites formed from [3H]E1 sulfate (E1S) and [3H]DHEA sulfate (DHEAS). The results have shown that the hydrolysis of each steroid sulfate is mediated by different particulate enzymes, which demonstrate optimal activity between pH 6.0-7.0. The analysis of enzyme kinetic data showed the Km values of E1S and DHEAS for their enzymes to be approximately 6.3 and 3.6 microM/L, respectively. Neither enzyme was subject to product inhibition. Androsterone sulfate and pregnenolone sulfate produced significant inhibition of E1, but not DHEA, sulfatase activity. E1S inhibited DHEA sulfatase competitively, with an approximate Ki of 11 microM, whereas DHEAS inhibited E2 sulfatase in a noncompetitive fashion, demonstrating an approximate Ki of 0.6 microM. Studies carried out with intact MCF-7 cultures using physiological concentrations of 3H-labeled E1S (2 nM) or DHEAS (1 microM) showed the accumulation of nonpolar metabolites during a 20-h incubation period. When cultures were incubated with similar concentrations of both steroid sulfates the apparent intracellular activity of E1 sulfatase was reduced by approximately 70%, whereas DHEA sulfatase activity remained unchanged. The results of these studies confirm the ability of MCF-7 cells to hydrolyze extracellular E1S and DHEAS, indicate that these reactions are mediated by different enzymes, and demonstrate that DHEAS is a potent inhibitor of MCF-7 E1 sulfatase. Circulating DHEAS, therefore, may substantially limit the ability of most postmenopausal breast cancers to use E1S as a substrate for intracellular estrogen biosynthesis.
Breast Neoplasms↗
Recent insight on the control of enzymes involved in estrogen formation and transformation in human breast cancer.
The great majority of breast cancers are in their early stage hormone-dependent and it is well accepted that estradiol (E2) plays an important role in the genesis and evolution of this tumor. Human breast cancer tissues contain all the enzymes: estrone sulfatase, 17beta-hydroxysteroid dehydrogenase, aromatase involved in the last steps of E2 bioformation. Sulfotransferases which convert estrogens into the biologically inactive estrogen sulfates are also present in this tissue. Quantitative data show that the 'sulfatase pathway', which transforms estrogen sulfates into the bioactive unconjugated E2, is 100-500 times higher than the 'aromatase pathway', which converts androgens into estrogens. The treatment of breast cancer patients with anti-aromatases is largely developed with very positive results. However, the formation of E2 via the 'sulfatase pathway' is very important in the breast cancer tissue. In recent years it was found that antiestrogens (e.g. tamoxifen, 4-hydroxytamoxifen), various progestins (e.g. promegestone, nomegestrol acetate, medrogestone, dydrogesterone, norelgestromin), tibolone and its metabolites, as well as other steroidal (e.g. sulfamates) and non-steroidal compounds, are potent sulfatase inhibitors. In another series of studies, it was found that E2 itself has a strong anti-sulfatase action. This paradoxical effect of E2 adds a new biological response of this hormone and could be related to estrogen replacement therapy in which it was observed to have either no effect or to decrease breast cancer mortality in postmenopausal women. Interesting information is that high expression of steroid sulfatase mRNA predicts a poor prognosis in patients with +ER. These progestins, as well as tibolone, can also block the conversion of estrone to estradiol by the inhibition of the 17beta-hydroxysteroid dehydrogenase type I (17beta-HSD-1). High expressison of 17beta-HSD-1 can be an indicator of adverse prognosis in ER-positive patients. It was shown that nomegestrol acetate, medrogestone, promegestone or tibolone, could stimulate the sulfotransferase activity for the local production of estrogen sulfates. This is an important point in the physiopathology of this disease, as it is well known that estrogen sulfates are biologically inactive. A possible correlation between this stimulatory effect on sulfotransferase activity and breast cancer cell proliferation is presented. In agreement with all this information, we have proposed the concept of selective estrogen enzyme modulators (SEEM). In conclusion, the blockage in the formation of estradiol via sulfatase, or the stimulatory effect on sulfotransferase activity in combination with anti-aromatases can open interesting and new possibilities in clinical applications in breast cancer.
17-Hydroxysteroid Dehydrogenases↗
Expression, localization, structural, and functional characterization of pFGE, the paralog of the Calpha-formylglycine-generating enzyme.
pFGE is the paralog of the formylglycine-generating enzyme (FGE), which catalyzes the oxidation of a specific cysteine to Calpha-formylglycine, the catalytic residue in the active site of sulfatases. The enzymatic activity of sulfatases depends on this posttranslational modification, and the genetic defect of FGE causes multiple sulfatase deficiency. The structural and functional properties of pFGE were analyzed. The comparison with FGE demonstrates that both share a tissue-specific expression pattern and the localization in the lumen of the endoplasmic reticulum. Both are retained in the endoplasmic reticulum by a saturable mechanism. Limited proteolytic cleavage at similar sites indicates that both also share a similar three-dimensional structure. pFGE, however, is lacking the formylglycine-generating activity of FGE. Although overexpression of FGE stimulates the generation of catalytically active sulfatases, overexpression of pFGE has an inhibitory effect. In vitro pFGE interacts with sulfatase-derived peptides but not with FGE. The inhibitory effect of pFGE on the generation of active sulfatases may therefore be caused by a competition of pFGE and FGE for newly synthesized sulfatase polypeptides.
Alanine↗
Rapid laboratory diagnostic of X-linked ichthyosis.
Steroid sulfatase and aryl sulfatase C activities were assayed simultaneously in peripheral blood leucocytes of 4 patients with X-linked ichthyosis (XLI) and 4 patients with autosomal-dominant ichthyosis; 11 healthy subjects served as controls. The deficiency of steroid sulfatase as well as of aryl sulfatase C found in leucocytes of patients with XLI was confirmed by the histochemical demonstration of aryl sulfatase C deficiency in skin sections. Although results are obtained earlier with the histochemical method than with the biochemical assay in leucocytes, several disadvantages brought us to the conclusion that the biochemical assay of microsomal sulfatase activity in leucocytes offers a fast and safe method for the identification of patients with XLI.
Arylsulfatases↗
Effect of nomegestrol acetate on estrogen biosynthesis and transformation in MCF-7 and T47-D breast cancer cells.
Although ovaries serve as the primary source of estrogen for pre-menopausal women, after menopause estrogen biosynthesis from circulating precursors occurs in peripheral tissues by the action of several enzymes, 17beta-hydroxysteroid dehydrogenase 1 (17beta-HSD1), aromatase and estrogen sulfatase. In the breast, both normal and tumoral tissues have been shown to be capable of synthesizing estrogens, and this local estrogen production can be implicated in the development of breast tumors. In these tissues, estradiol (E(2)) can be synthesized by three pathways: (1) estrone sulfatase transforms estrogen sulfates into bioactive estrogens, (2) 17beta-HSD1 converts estrone (E(1)) into E(2), (3) aromatase which converts androgens into estrogens is also present and contributes to the in situ synthesis of active estrogens but to a far lesser extent than estrone sulfatase. Quantitative assessment of E(2) formation in human breast tumors indicates that metabolism of estrone sulfate (E(1)S) via the sulfatase pathway produces 100-500 times more E(2) than androgen aromatization. Breast tissue also possesses the estrogen sulfotransferase involved in the conversion of estrogens into their sulfates that are biologically inactive. In the present review, we summarized the action of the 19-nor-progestin nomegestrol acetate (NOMAC) on the sulfatase, 17beta-HSD1 and sulfotransferase activities in the hormone-dependent MCF-7 and T47-D human breast cancer cell lines. Using physiological doses of substrates NOMAC blocks very significantly the conversion of E(1)S to E(2). It inhibits the transformation of E(1) to E(2). NOMAC has a stimulatory effect on sulfotransferase activity in both cell lines, with a strong stimulating effect at low doses but only a weak effect at high concentrations. The effects on the three enzymes are always stronger in the progesterone-receptor rich T47-D cell line as compared with the MCF-7 cell line. Besides, no effect is found for NOMAC on the transformation of androstenedione to E(1) in the aromatase-rich choriocarcinoma cell line JEG-3. In conclusion, the inhibitory effect provoked by NOMAC on the enzymes involved in the biosynthesis of E(2) (sulfatase and 17HSD pathways) in estrogen-dependent breast cancer, as well as the stimulatory effect on the formation of the inactive E(1)S, can open attractive perspectives for future clinical trials.
17-Hydroxysteroid Dehydrogenases↗
Paradoxical effect of estradiol: it can block its own bioformation in human breast cancer cells.
The great majority of breast cancers are in their early stage hormone-dependent and it is well accepted that estradiol (E(2)) plays an important role in the genesis and evolution of this tumor. Human breast cancer tissues contain all the enzymes: estrone sulfatase, 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD), aromatase, involved in the last steps of E(2) bioformation in this tissue. Quantitative data show that the 'sulfatase pathway', which transforms estrogen sulfates into the bioactive unconjugated E(2), is 100-500 times higher than the 'aromatase pathway' which converts androgens into estrogens. In this paper we explore the effect of E(2) on the sulfatase activity using two hormone-dependent human breast cancer cells: MCF-7 and T-47D. The action of E(2) on the sulfatase activity was evaluated by the conversion of estrone sulfate (E(1)S) into E(2). The cells were incubated in Minimal Essential Medium (MEM) containing 5% steroid-depleted fetal calf serum and incubated with physiological concentrations of [(3)H]E(1)S (5 x 10(-9) M) alone (control) or in the presence of E(2) (5 x 10(-10) to 5 x 10(-5) M) for 24 h at 37 degrees C. It was found that E(2) is a potent inhibitory agent of the estrone sulfatase activity in both cell lines. A low concentration of E(2): 5 x 10(-9) M decreases the sulfatase activity by 67% in MCF-7 cells and 57% in T-47D cells. More than 80% of the decrease in the formation of E(2) was obtained with the dose of 5 x 10(-7) M in both cell lines. It is concluded that this paradoxical effect of E(2) adds a new biological response of this hormone and could be related to estrogen replacement therapy in which it was observed to have either no effect or to decrease breast cancer mortality in postmenopausal women. Preliminary results are indicated in the Proceedings of the 14th International Symposium of the Journal of Steroid Biochemistry & Molecular Biology (Quebec, Canada, 24-27 June 2000) [J. Steroid Biochem. Molec. Biol. 76 (2001) 95-104](1) and presented at the 83rd Annual Meeting of the Endocrine Society (Denver, USA, 20-23 June 2001 (abstract no. P2-615).
Breast Neoplasms↗
Synthesis and biological activity of the superestrogen (E)-17-oximino-3-O-sulfamoyl-1,3,5(10)-estratriene: x-ray crystal structure of (E)-17-oximino-3-hydroxy-1,3,5(10)-estratriene.
Steroid sulfatases regulate the formation of estrogenic steroids which can support the growth of endocrine-dependent breast tumors. Therefore, the development of potent steroid sulfatase inhibitors could have considerable therapeutic potential. Several such inhibitors have now been developed including estrone 3-O-sulfamate (EMATE, 1), which shows potent active site-directed inhibition. However, EMATE was subsequently shown to be also a potent estrogen. In an attempt to reduce the estrogenicity while retaining the potent sulfatase inhibitory properties associated with this type of molecule, (E)-17-oximino-3-O-sulfamoyl-1,3,5(10)-estratriene (5) (estrone oxime 3-O-sulfamate, OMATE) was synthesized. The X-ray crystal structure of (E)-17-oximino-3-hydroxy-1,3,5(10)-estratriene (4) (estrone oxime) demonstrated the presence of only one geometrical isomer [anti-isomer, (E)]. OMATE potently inhibited estrone sulfatase (E1-STS) activity and was similar to EMATE (>99% inhibition at 0.1 microM in MCF-7 breast cancer cells). It was also evaluated in vivo for its estrogenicity and ability to inhibit sulfatase activity. While it was equipotent with EMATE in vivo as a sulfatase inhibitor, it surprisingly had a stimulatory effect on uterine growth in ovariectomized rats about 1.5-fold greater than that of EMATE. Thus, OMATE possesses potential as a superestrogen and modification at C-17 is identified as a useful route for enhancement of estrogenicity in sulfamate-based estrogens.
Animals↗
Human placental sterylsulfatase. Interaction of the isolated enzyme with substrates, products, transition-state analogues, amino-acid modifiers and anion transport inhibitors.
The enzymatic properties of a homogeneous sterylsulfatase preparation isolated from human term placenta were studied. The enzyme exhibited both arylsulfatase and sterylsulfatase activity: it catalysed the hydrolysis of sulfuric acid esters of (in the order of decreasing specific activity) non-steroidal phenols, of a phenolic steroid, and of neutral 3 beta-, 21- and (though at a very low rate) 17 beta-hydroxysteroids. However, among all the substrates tested only the 3-sulfates of phenolic and neutral steroids exhibited high affinity towards the sulfatase. Vitamin D3 sulfate was not hydrolysed by the sterylsulfatase but strongly inhibited its activity. The products of the catalytic reaction, free steroids or phenols as well as the sulfate anion or analogues thereof, likewise interfered with the enzyme's activity. Ki values of unconjugated steroids were ten- to hundredfold higher than Km values of the respective sulfoconjugates. Inorganic sulfate only slightly inhibited the sulfatase activity; its inhibitory potency, however, increased in a time-dependent manner when it was preincubated with the enzyme prior to assay. In contrast to sulfate, the hypothetical transition-state analogues sulfite and vanadate acted as strong inhibitors of the sulfatase activity. According to the results of an analysis of the effect of pH on sterylsulfatase kinetics, enzyme constituents with pK values of approximately 5.8 and 8.0 are involved in a general acid-base catalysed reaction. Treatment of the sulfatase with amino-acid side chain modifying reagents directed against arginine, cysteine, cystine, serine or tyrosine residues did not result in significant alteration of its activity. Diethyl-pyrocarbonate known to react primarily with histidyl groups, however, rapidly inactivated the enzyme; this inactivation reaction was markedly retarded in the presence of substrate. Histidine thus appears to be essential for the catalytic activity of the sulfatase. Taken together, the present results reveal a considerable similarity between the catalytic mechanism of human placental sterylsulfatase and the ones already proposed for the lysosomal arylsulfatases A and B. Taurocholate, salicylate, ouabain, and 4,4'-substituted stilbene-2,2'-disulfonates are well known inhibitors of carrier-mediated transport of anions across cellular membranes. With the exception of ouabain, these compounds likewise turned out to inhibit the enzymatic hydrolysis of steryl sulfates; the pattern of dose dependences of their interference with the sulfatase activity resembles the one reported for inhibition of anion transport. Since the sterylsulfatase in vivo strongly is associated with cellular membranes including the plasma membrane of the syncytiotrophoblast, this finding supports the speculation that similar molecular structures may be involved in both placental transport and hydrolysis of anionic steryl sulfates.
Amino Acids↗
The selective estrogen enzyme modulators in breast cancer: a review.
It is well established that increased exposure to estradiol (E(2)) is an important risk factor for the genesis and evolution of breast tumors, most of which (approximately 95-97%) in their early stage are estrogen-sensitive. However, two thirds of breast cancers occur during the postmenopausal period when the ovaries have ceased to be functional. Despite the low levels of circulating estrogens, the tissular concentrations of these hormones are significantly higher than those found in the plasma or in the area of the breast considered as normal tissue, suggesting a specific tumoral biosynthesis and accumulation of these hormones. Several factors could be implicated in this process, including higher uptake of steroids from plasma and local formation of the potent E(2) by the breast cancer tissue itself. This information extends the concept of 'intracrinology' where a hormone can have its biological response in the same organ where it is produced. There is substantial information that mammary cancer tissue contains all the enzymes responsible for the local biosynthesis of E(2) from circulating precursors. Two principal pathways are implicated in the last steps of E(2) formation in breast cancer tissues: the 'aromatase pathway' which transforms androgens into estrogens, and the 'sulfatase pathway' which converts estrone sulfate (E(1)S) into E(1) by the estrone-sulfatase. The final step of steroidogenesis is the conversion of the weak E(1) to the potent biologically active E(2) by the action of a reductive 17beta-hydroxysteroid dehydrogenase type 1 activity (17beta-HSD-1). Quantitative evaluation indicates that in human breast tumor E(1)S 'via sulfatase' is a much more likely precursor for E(2) than is androgens 'via aromatase'. Human breast cancer tissue contains all the enzymes (estrone sulfatase, 17beta-hydroxysteroid dehydrogenase, aromatase) involved in the last steps of E(2) biosynthesis. This tissue also contains sulfotransferase for the formation of the biologically inactive estrogen sulfates. In recent years, it was demonstrated that various progestins (promegestone, nomegestrol acetate, medrogestone, dydrogesterone, norelgestromin), tibolone and its metabolites, as well as other steroidal (e.g. sulfamates) and non-steroidal compounds, are potent sulfatase inhibitors. Various progestins can also block 17beta-hydroxysteroid dehydrogenase activities. In other studies, it was shown that medrogestone, nomegestrol acetate, promegestone or tibolone can stimulate the sulfotransferase activity for the local production of estrogen sulfates. All these data, in addition to numerous agents which can block the aromatase action, lead to the new concept of 'Selective Estrogen Enzyme Modulators' (SEEM) which can largely apply to breast cancer tissue. The exploration of various progestins and other active agents in trials with breast cancer patients, showing an inhibitory effect on sulfatase and 17beta-hydroxysteroid dehydrogenase, or a stimulatory effect on sulfotransferase and consequently on the levels of tissular levels of E(2), will provide a new possibility in the treatment of this disease.
17-Hydroxysteroid Dehydrogenases↗
Regulation of macrophage dehydroepiandrosterone sulfate metabolism by inflammatory cytokines.
Metabolism of dehydroepiandrosterone sulfate (DHEAS) to dehydroepiandrosterone (DHEA) occurs within specific anatomical compartments in vivo through the actions of the enzyme DHEAS sulfatase. This enzymatic activity facilitates the conversion of hydrophilic DHEAS to the hydrophobic species DHEA, which can then be further metabolized to other steroid hormones. High levels of DHEAS sulfatase reside in tissues where the biological activity of DHEA or its downstream metabolites regulate cellular function. Therefore, control over the activity of DHEAS sulfatase may represent an important regulatory process for the production of DHEA and its metabolites. Homogeneous populations of macrophages from normal mice were found to effectively convert DHEAS to DHEA in vitro. DHEAS sulfatase activity could be markedly depressed after exposure of these cells to a variety of nonspecific macrophage activators [i.e. zymosan, polyinosine/cytosine, heat-killed bacteria, or bacterial lipopolysaccharide (LPS)]. Inhibition of DHEAS metabolism was found to require protein synthesis, because temporary abrogation of protein synthesis with cycloheximide eliminated the ability of LPS to depress the conversion of DHEAS to DHEA. Additionally, exposure of LPS-nonresponsive macrophages to supernatants derived from LPS-treated BALB/c macrophages inhibited their ability to convert DHEAS to DHEA. Potent inhibition of sulfatase activity could be achieved by directly exposing murine macrophages to interferon-alpha (IFN alpha), IFN beta, or tumor necrosis factor-alpha, but not interleukin-1, interleukin-6, granulocyte-macrophage colony-stimulating factor, transforming growth factor-beta, platelet-derived growth factor, or the T-cell product IFN gamma. Our results indicate that macrophage metabolism of DHEAS to DHEA is down-regulated after cellular activation. Furthermore, inhibition of DHEAS sulfatase activity appears to be mediated through the actions of the inflammatory cytokines tumor necrosis factor-alpha and IFN alpha/beta.
Animals↗
Estrone sulfate sulfohydrolase in the developing brain and pituitary of rat, mouse and guinea pig.
The pattern of estrone sulfate sulfohydrolase (estrogen sulfatase) development in the brain of rat, mouse and guinea pig has been established by assaying whole homogenates. Activity was measurable in each species from the fetal state to adulthood. Maximum brain content was reached at about 20 days of age in rat, 14 days in mouse and 15 days in guinea pig. A considerable decrease occurred between 14 days and adulthood in mouse and lesser decreases were seen in rat and guinea pig. The subcellular distribution of enzyme in rat and mouse brain appeared to change from the immature to the adult state. No major differences in enzyme activity occurred between the sexes at any age. Tissue concentration of enzyme in the hypothalamic-preoptic area of rat and mouse was similar to that in the remainder of the brain. In guinea pig the brain concentration was slightly lower than that of the hypothalamic-preoptic region. Sulfatase content of the pituitary was low in all 3 species but the tissue concentration was considerably higher than that of brain, particularly in rat and mouse. Apparent Km values for brain sulfatase were in the range 6-17 microM, with no striking sex difference. Apparent Km's for pituitary sulfatase of immature rat and guinea pig were similar to those for brain in the same animals but that for mouse pituitary (0.9 microM) was much lower. It is unlikely that brain or pituitary sulfatase is by itself, a major factor in making available potentially active estrogen for use during differential sex development in these species.
Aging↗
Gene therapy for metachromatic leukodystrophy.
Metachromatic leukodystrophy (MLD) is an inherited metabolic disease which is characterized by a deficiency of arylsulfatase A (ASA). This deficiency causes progressive accumulation of cerebroside sulfate in oligodendrocytes (OL) in the brain, resulting in dysmyelination. Approaches being developed by the authors to treating MLD are based on direct delivery of ASA genes into the brain. In the present report, it has been shown that the recombinant adenovirus (Adex1SRLacZ) was able to transduce the OL very efficiently. Moreover, primary fibroblasts from MLD patients were exposed to recombinant adenovirus expressing the ASA gene (Adex1SRASA) and the cells expressed the transgene. The influence of overexpression of ASA on the activity of other sulfatases was also tested in fibroblasts from patients with MLD using a retrovirus vector (MFG-ASA). It was demonstrated that the overexpression of ASA reduces the activity of various sulfatases by a small amount but does not induce an accumulation of glycosaminoglycan. These results indicate that the influence of ASA overexpression on other sulfatases is different from that of the N-acetygalactosamine-4-sulfatase overexpression in a previous report. It was concluded that the correction of ASA deficiency by a recombinant adenovirus that potentially could be used to transfer the gene to the brain, and gene therapy for MLD based on gene transfer of the ASA gene to mutant cells will be feasible because the overexpression of ASA in cells does not lead to profound deficiency of other sulfatases or result in a new phenotype.
Adenoviridae↗
Overexpression of arylsulfatase A gene in fibroblasts from metachromatic leukodystrophy patients does not induce a new phenotype.
We tested the influence of overexpression of arylsulfatase A (ASA) on the activity of other sulfatases in fibroblasts from patients with metachromatic leukodystrophy (MLD). We demonstrated that the overexpression of ASA reduces the activity of various sulfatases by a small amount but does not induce an accumulation of glycosaminoglycan. Our results indicate that influence of ASA overexpression on other sulfatases is different from that of N-acetyl-galactosamine-4-sulfatase overexpression reported by Anson et al. We conclude that gene therapy for MLD based on the transfer of a normal ASA gene to mutant cells will be feasible because the overexpression of ASA peptides in cells does not lead to profound deficiency of other sulfatases or result in a new phenotype.
Cells, Cultured↗
Development of an assay for the detection of mucopolysaccharidosis type VI patients using dried blood-spots.
BACKGROUND: Mucopolysaccharidosis type VI (MPS VI) is a lysosomal storage disorder (LSD), which is caused by a deficiency in the enzyme N-acetylgalactosamine 4-sulfatase (4-sulfatase). MPS VI is characterized by severe skeletal abnormalities, somatic tissue pathology and early death. Treatment possibilities include bone marrow transplantation (BMT) and enzyme replacement therapy (ERT; currently in phase III clinical trial). Early diagnosis of MPS VI will allow treatment before the onset of irreversible pathology. METHODS: Sensitive immune assays have been developed to detect 4-sulfatase protein and activity in normal control and MPS VI blood-spots. RESULTS: Dried blood-spots from MPS VI patients contained no detectable 4-sulfatase protein and activity, compared to 3.5-21 microg/L of 4-sulfatase protein and 291-1298 nmol/min/L of activity for normal human controls. In this evaluation study, the assay was sensitive and 100% specific, allowing reliable detection of individuals with MPS VI. CONCLUSIONS: The assays reported here have the potential to detect MPS VI patients using dried blood-spots.
Case-Control Studies↗