Maroteaux-Lamy Research Articles

Molecular analysis of mucopolysaccharidosis type VI in Iranian patients; the influence of founder effect and consanguinity.

Mucopolysaccharidosis type VI (MPS VI), also known as Manteaux-Lamy syndrome, is an autosomal recessive lysosomal storage disorder caused by deficiency of the enzyme arylsulfatase B(ARSB). This syndrome is progressive and affects many tissues and organs, leading to inflammation and scarring. The classic clinical features of Maroteaux-Lamy syndrome are significant impairment of the osteoarticular system with dysostosis multiplex, short stature and motor dysfunction. The rate at which symptoms appear and worsen can vary between affected individuals. Mutations in the ARSB gene are responsible for MPS VI. We investigated the clinical presentation and molecular basis of patients with MPS VI for the first time in Yazd province, Iran. Of the 52 people who took part in this project, there were 13 probands. Whole exome sequencing (WES) was performed in 2 of them and the nominated mutation in the ARSB (c.430G > A) was verified by Sanger sequencing in the remaining patients. All patients had parental consanguinity, except for one family in which the parents were unrelated. All patients were of Fars ethnicity and had characteristic phenotypes such as severe short stature, cardiac involvement, coarse facial features, and corneal opacities. Sequence analysis of the ARSB gene revealed a pathogenic homozygous missense mutation c.430G > A (p. Gly144Arg) in all patients. This type of mutation influenced the phenotypes of the severe patients. These results expand the genetic databases of Iranian patients with MPS VI and would be very helpful for the high-risk families to accelerate the detection of carriers and to perform prenatal testing for the disorder in this population in a cost-effective manner. There is a possibility that other unknown mutations are responsible for the disease. The decision to screen for and detect carriers of this disease at a national level is awaited. The results of the present study could be an asset for married families in part of the city of Meybod. The results offer a way for early detection of patients and carriers of the disease.

Multi-year enzyme expression in patients with mucopolysaccharidosis type VI after liver-directed gene therapy.

Mucopolysaccharidosis type VI (MPS VI) is due to a deficiency of the lysosomal enzyme arylsulfatase B (ARSB) that results in multi-organ accumulation of glycosaminoglycans (GAGs). Limitations of current treatments prompted the development of a liver-directed gene therapy clinical trial for MPS VI. We report the long-term follow-up of patients with MPS VI who discontinued enzyme replacement therapy (ERT) and received a single intravenous infusion of high-dose (6×1012 genome copies/kg) recombinant adeno-associated virus serotype 8 (AAV8) vector expressing ARSB under the control of a liver-specific promoter (ClinicalTrials.gov: NCT03173521). Primary outcomes were safety and urinary GAG excretion. Secondary outcomes were endurance and respiratory function. Median follow-up time was 45months (n= 4, three females and one male; age range: 5-10 years). No late-emergent safety events were observed. Patients showed sustained serum ARSB activity (38%-67% of mean healthy reference values), a modest increase in urinary GAG concentrations, and no relevant changes in endurance, cardiac, or pulmonary function. In one of the four patients, ERT was restarted because of elevated urinary GAGs without decreased serum ARSB activity up to about 2.5 years after gene transfer. Liver and spleen size remained within the reference ranges. A single intravenous administration of AAV8.TBG.hARSB was safe and resulted in sustained ARSB expression and a modest increase in urinary GAGs in most patients, thus supporting liver-directed gene therapy for MPS VI. This study was sponsored by the Telethon Foundation ETS, the European Union, the Isaac Foundation, and the Italian Ministry of University and Research.

A rare presentation of Maroteaux-Lamy syndrome with secondary glaucoma – A case report and review of literature

We present a rare case of MPS VI (Manteaux-Lamy syndrome) with a bilateral cloudy cornea, coarse facies, large tongue, chest deformities, abdominal hernia, and skeletal deformities. Blood tests for lysosomal enzymes showed the absence of serum arylsulfatase B, which confirmed the diagnosis. Ocular examination revealed corneal clouding and an increase in intraocular pressure (IOP) in both eyes. Though less common, glaucoma is difficult to diagnose and manage due to inappropriate IOP recording and poor visualization of the fundus details due to corneal clouding in MPS VI. A detailed evaluation of these patients is required to avoid overdiagnosis.

The importance of geographic and sociodemographic aspects in the characterization of mucopolysaccharidoses: a case series from Ceará state (Northeast Brazil).

Geographic and sociodemographic aspects may influence the natural history and epidemiology of mucopolysaccharidoses (MPS). The main objective in this work was to evaluate the clinical, molecular, and geographic profile of MPS in a population from Ceará (Northeast Brazil). For this, we have performed a descriptive cross-sectional study based on clinical evaluation, interviews with patients and/or family members, and review of medical records of 76 MPS patients. MPS II was the most common type, with the most affected individuals presenting missense pathogenic variants. Patients with MPS I proved to be the most severe clinical phenotype, presenting the first symptoms (mean: 7.1 months; SD = 4.5) and being diagnosed earlier (2.2 years; SD = 2.1) in comparison with the other types. In addition, we have shown that 13 individuals with MPS VI were born of consanguineous marriages in small, nearby cities, in a place where geographical isolation, consanguinity, and clusters of genetic diseases were previously reported. Ten of these individuals (at least, seven different families) presented a rare pathogenic variant in the ARSB gene, c.1143-8T > G in homozygosity, previously reported only among Iberian and South American patients. The results presented here provide a comprehensive picture of MPS in an important state of the Brazilian Northeast, a region that concentrates many risk factors for rare genetic diseases, such as endogamy, inbreeding, and reproductive isolation. We discuss the possible evolutionary processes and biosocial dynamics that can help to explain this finding in terms of population medical genetics and public health.

Real-world pharmacovigilance analysis of galsulfase: a study based on the FDA adverse event reporting system (FAERS) database.

Associated with enzyme deficiencies causing glycosaminoglycans (GAGs) accumulation, mucopolysaccharidosis type VI (MPS VI) is lysosomal storage disorder. In the treatment of MPS VI, galsulfase (Naglazyme) is commonly used as an enzyme replacement therapy (ERT). There remains a need for comprehensive real-world data on its safety and associated adverse events (AEs). An analysis of the FDA Adverse Event Reporting System (FAERS) database will be conducted to identify potential risks and adverse reactions associated with galsulfase in real-life settings. The FAERS database was used to extract data from Q2 2005 to Q4 2023. A total of 20,281,876 reports were analyzed after duplicate elimination, with 3,195 AE reports related to galsulfase identified. The association between galsulfase and AEs was investigated by utilizing four algorithms: reporting odds ratio (ROR), proportional reporting ratio (PRR), Bayesian confidence propagation neural network (BCPNN), and multi-item gamma Poisson shrinker (MGPS). The analysis focused on the timing of onset, signs of AEs, and clinical significance. Twenty seven organ systems were involved, and significant system organ classes (SOCs) included respiratory, thoracic and mediastinal disorders, and infections and infestations. At the PT level, 72PTs corresponding to 15 SOCs were identified, with some AEs not previously mentioned in the product label. AEs associated with galsulfase had a median onset time of 1,471days, with over half of the cases occurred within the first 5years of treatment initiation. This investigation delivers an exhaustive and indicative assessment of galsulfase's safety profile, grounded in authentic, real-world evidence. The findings emphasis the importance of continuous safety surveillance and the emergence of new AEs. The identification of previously unreported urologic adverse events, such as glomerulonephritis membranous and nephritic syndrome, warrants further investigation. The study emphasizes the need for enhanced pharmacovigilance to ensure patient safety and the effectiveness of galsulfase treatment.

Consensus-based expert recommendations on the management of MPS IVa and VI in Saudi Arabia

BackgroundMucopolysaccharidosis type IVa (Morquio A syndrome) and mucopolysaccharidosis type VI (Maroteaux-Lamy syndrome) are rare inherited lysosomal storage diseases associated with significant functional impairment and a wide spectrum of debilitating clinical manifestations. These conditions are thought to have higher-than-average prevalence rates in Saudi Arabia due to high rates of consanguineous marriage in the country. There are several unmet needs associated with the management of these diseases in Saudi Arabia.Main bodyThe aim of this manuscript is to contextualize unmet management needs and provide recommendations to optimize diagnosis, multidisciplinary care delivery, and local data generation in this disease area. An expert panel was assembled comprising seven consultant geneticists from across Saudi Arabia. The Delphi methodology was used to obtain a consensus on statements relating to several aspects of mucopolysaccharidosis types IVa and VI. A consensus was reached for all statements by means of an online, anonymized voting system. The consensus statements pertain to screening and diagnosis, management approaches, including recommendations pertaining to enzyme replacement therapy, and local data generation.ConclusionThe consensus statements presented provide specific recommendations to improve diagnostic and treatment approaches, promote multidisciplinary care and data sharing, and optimize the overall management of these rare inherited diseases in Saudi Arabia.

ASSESSMENT OF THYROID FUNCTION AND ULTRASONOGRAPHIC FINDINGS IN PATIENTS WITH MUCOPOLYSACCHARIDOSIS

Objective: The thyroid gland, with its high vascularity and low proliferation index of thyrocytes, is highly susceptible to storage diseases, however it has not been evaluated adequately in patients with in mucopolysaccharidosis (MPS). Therefore, the aim of this study is to assess the function, morphology, B- mode, and Doppler ultrasonography features of the thyroid gland in pediatric and adolescent patients with MPS and to evaluate whether the thyroid gland is involved in this disease. Material and Methods: Thyroid hormone functions were measured in all patients, and B-mode ultrasound and color Doppler imaging were performed. Results: Eight boys and 17 girls with MPS were included in the study. Eight patients were diagnosed with MPS I, 2 with MPS II, 3 with MPS III, 3 with MPS IVA, and 9 with MPS VI. Nineteen patients were receiving enzyme replacement therapy, while three patients diagnosed with MPS III remained untreated due to the unavailability of treatment options. Thyroid hormone levels were within normal limits for all patients. B-Mode ultrasound imaging revealed slightly heterogeneous echo texture in only 2 (8%) patients, both with MPS VI. Except for one patient with MPS VI, all color Doppler assessments were within normal limits. Conclusion: The results of our study demonstrate that both thyroid function tests and thyroid gland morphology are normal in MPS through childhood and adolescence. Therefore, we believe that thyroid gland dysfunction does not play a crucial role in the development of symptoms such as growth retardation, dry skin, coarse facial features, and intellectual disability, which could potentially be attributed to thyroid dysfunction. Instead, we think that these findings are more likely attributed to the primary disease involvement process

Abstract 5979: Recombinant N-acetylgalactosamine-4-sulfatase (arylsulfatase B; ARSB) inhibits lung metastases in murine B16F10 syngeneic tumor model

Abstract Activity of the enzyme N-acetylgalactosamine-4-sulfatase (Arylsulfatase B: ARSB), which removes the 4-sulfate group at the non-reducing end of chondroitin 4-sulfate (C4S) and dermatan sulfate, is reduced in several malignant cell lines and human tissues, including melanomas, mammary, prostate, and colon. Following tail vein injection of B16F10 melanoma cells in 12-week-old female C57BL/6J mice (n=11) and subsequent treatment by tail vein injection of bioactive, recombinant human ARSB (0.2 mg/kg), on days 2 and 7, development of metastatic lung lesions was markedly reduced. The average number of lesions declined from mean value of 114 (range: 10-278; n=5) to mean value of 2.5 (range: 0-9; n=6). These findings are consistent with our previous report of significant increase in survival and decrease in size of B16F10 subcutaneous melanomas in C57BL/6J mice treated with exogenous ARSB. The underlying mechanisms leading to inhibition of melanoma proliferation have profound impact on vital signaling pathways and transcriptional events. These pathways involve more or less binding with C4S when ARSB activity is modified. Notably, galectin-3 binding with C4S increases following exogenous ARSB, leading to decline in free nuclear galectin-3. This leads to reduced expression of the melanoma biomarker chondroitin sulfate proteoglycan CSPG)-4; also known as melanoma-associated chondroitin sulfate proteoglycan (MCSP). Expression of Programmed Death-Ligand 1 (PD-L1) is also reduced, declining from 1.34 ± 0.23 ng/mg protein (n=5) to 0.50 ± 0.05 ng/mg protein (n=6) following ARSB treatment. Inverse to the effect on galectin-3, SHP2, the ubiquitous non-receptor tyrosine phosphatase (PTPN11), binds less to C4S following treatment with exogenous ARSB. The resulting activation of SHP2 impacts on MAPK signaling, reducing phospho-ERK1/2 and phospho(T180/Y182)-p38-MAPK. These effects contribute to decline in matrix metalloproteinases MMP2 and MMP9 and thereby restrain invasiveness and metastasis. Following treatment with exogenous ARSB, the serum MMP2 declined from 267 ± 38 (ng/ml; n=5) to 121 ± 16 ng/ml (n=6), consistent with the observed decline in melanoma lesions. The impact of ARSB on signaling pathways and transcriptional events demonstrates how modification of a critical sulfation and the resulting impact on binding with C4S influences vital cell processes and can suppress tumor development. Recombinant human ARSB is an approved agent for the treatment of Mucopolysaccharidosis VI and is used safely and effectively for this congenital deficiency of ARSB. Exogenous ARSB may become an effective treatment for acquired deficiency of ARSB in melanoma. Citation Format: Joanne Kramer Tobacman, Sumit Bhattacharyya, Insug O-Sullivan. Recombinant N-acetylgalactosamine-4-sulfatase (arylsulfatase B; ARSB) inhibits lung metastases in murine B16F10 syngeneic tumor model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5979.

Humanistic burden of mucopolysaccharidoses: a systematic literature review

Objective To systematically review the literature and summarize the health-related quality-of-life (HRQoL) of patients undergoing treatment for mucopolysaccharidoses (MPS), a rare, hereditary lysosomal storage disorder. Methods A systematic review was performed in accordance with PRISMA guidelines to identify research studies that describe the humanistic burden of MPS. A comprehensive literature search was conducted in EMBASE, MEDLINE, and eligible conferences were screened to include applicable abstracts. Results Of 870 identified articles, 15 studies reported the HRQoL burden of patients with MPS undergoing or with a history of ERT and/or HSCT. These studies include patients of MPS I (n = 2), MPS II (n = 4), MPS IV (n = 6), MPS VI (n = 1), and subtype not mentioned (n = 2). Although the quality-of-life of MPS patients is influenced by time of diagnosis, pain, cognitive involvement, severity of disease, mobility, dependence, and time of treatment initiation, the HRQoL scores of MPS patients across all the scales were below the median reference population scores across all dimensions. This is seen in comparison to healthy participants but also in comparison to patients with other chronic illnesses. The multi-organ involvement, neurological impairment, pain, and morbidity associated with the condition not only affects activity of daily living but also affects social functioning, emotional status, employment status among adults, and school functioning among children. Conclusions This systematic literature review revealed the substantial humanistic burden of individuals affected by MPS as well as caregivers. Significant variation in HRQoL scores was observed, however studies indicate that the quality-of-life of MPS patients is influenced primarily by severity of disease (MPS type and phenotype), and then by time of diagnosis, pain, cognitive involvement, mobility, dependence, and time of treatment initiation. Further studies are needed to assess the global humanistic burden of MPS, particularly in MPS III, VI, VII, and IX subtypes, in adults, and for a longer follow-up period. Considering the vast array of HRQoL assessment tools available and used in this study, researchers should also consider using scales with condition-specific measures to ensure appropriate estimates of effectiveness.

Cardiac Involvement in Pediatric Mucopolysaccharidoses Patients and their Genetic Profile: A Retrospective Single-center Study

Abstract Background: Mucopolysaccharidoses (MPS) are rare metabolic disorders of monogenic inheritance, with varying degrees of cardiac involvement due to undegraded glycosaminoglycans getting aggregated in the spongiosa of the cardiac valves, the myocardium, and myointima of the coronary arteries. This study is an effort to understand the cardiac involvement and genetic pattern of pediatric MPS patients at a tertiary care center in South India. Methods: This descriptive study was done by examining records in our hospital database for MPS patients in the age group of 0–15 years, diagnosed between January 2014 and January 2023. Of these patients, 37 patients with echocardiographic loops available in the hospital system were reevaluated by a single pediatric cardiologist to avoid observer bias. The underlying genetic spectrum was also reviewed. Results: The cohort comprised 67.5% of males and a median age of 9.8 years (interquartile range: 6.5–14.9 years) with a distribution of 37.8% MPS I, 32.4% MPS II, 13.5% MPS IV, and 10.8% MPS VI. Early cardiac involvement in the form of valvar thickening, predominantly left sided (mitral [92%] >aortic [38%]), was seen across all MPS subtypes. We also noted an increased involvement of the tricuspid valve (38%) in our cohort. Moderate–severe valvar involvement was seen in 16% of the cohort, mostly MPS I, II, and VI patients, and more in the second half of the age group (>6 years), suggesting an age-associated worsening of cardiac lesions. Genetic analysis done in 68% of the cohort detected 61% of pathogenic variants, with a predominance of missense mutation (43%). However, no genotype–cardiac phenotype correlation could be ascertained. Conclusions: We identified a high proportion of cardiac abnormalities in our pediatric MPS cohort, which ranged from isolated valvar thickening to a more severe clinical picture, including moderate-to-severe valvular insufficiency and/or stenosis and left ventricular hypertrophy. Cardiac pathology is an early manifestation and a known cause of mortality in many MPS subtypes. Echocardiography is a key diagnostic technique for early detection, careful monitoring, and guidance in the initiation of a timely intervention that will help curb its progression. Hence, the need arises to raise awareness among the primary caretakers of this subset of patients on the need for early cardiac evaluation with a detailed echocardiography.

A phase 2, randomized, double-blind, placebo-controlled, multicentre study to evaluate the efficacy and safety of pentosan polysulfate sodium in treating subjects with mucopolysaccharidosis VI: Study update

A phase 2, randomized, double-blind, placebo-controlled, multicentre study to evaluate the efficacy and safety of pentosan polysulfate sodium in treating subjects with mucopolysaccharidosis VI: Study update

Biomarkers of Glycosaminoglycans (GAG) accumulation in patients with mucopolysaccharidosis type VI—LeukoGAG, Corneal Opacification (COM) and Carotid Intima Media Thickening (CIMT)

Mucopolysaccharidosis type VI (MPS VI) is an autosomal recessive lysosomal storage disorder characterized by deficient activity of arylsulfatase B enzyme (ASB) resulting in cellular accumulation of dermatan sulfate (DS) and chondroitin sulfate (CS) that leads to cell injury. Urinary glycosaminoglycans (GAG) are often used as a biomarker in MPS diseases for diagnosis and to monitor treatment efficacy. This study evaluated leukocyte GAGs (leukoGAG) and skin GAGs as alternate biomarkers representing intracellular GAG changes in patients with MPS VI and treated with enzyme replacement therapy (ERT). In addition, we evaluated corneal opacification measurements (COM) and carotid intima media thickness (CIMT) as indicators of GAG accumulation and tissue injury. The study was performed in a serial two-step design in a single center. A quantitative method to measure leukoGAG levels in leukocytes was developed in Study 1 to compare the GAG levels between MPS VI patients and a control group and to assess correlations between leukoGAG and urineGAG. Study 2 validated the leukoGAG measurement, assessed the effect of ERT infusion on leukoGAG and ASB activity in leukocytes, identified correlations between leukoGAG and other biomarkers, and assessed differences in GAG accumulation between MPS VI patients and control subjects. In Study 1, leukoCS and leukoDS levels were significantly higher in the MPS VI group than the control group (leukoCS: 37.9 ± 10.2 and 2.9 ± 1.5 μg/μg protein, respectively, p = 0.005; leukoDS: 0.26 ± 0.2 and 0.0 ± 0.0 μg/μg protein, respectively, p = 0.028) with positive correlations between leukoCS and urine CS and leukoDS and urineDS. In Study 2, leukoCS (32.0 ± 11.8 vs 6.9 ± 3.1 μg/mg protein, p = 0.005) and leukoDS (0.4 ± 0.1 and 0.2 ± 0.1 μg/mg protein, p = 0.020) were significantly higher compared with control subjects. Thus, these results highlight the potential of leukoGAG as a new biomarker representing intracellular GAG accumulation in MPS VI patients and may be valuable for patient management.

Long-term outcome of hematopoietic stem cell transplantation in two children with Mucopolysaccharidosis

To explore the long-term efficacy of allogeneic hematopoietic stem cell transplantation (alloHSCT) in patients with Mucopolysaccharidosis (MPS), which has rarely been reported in China. A 18-month-old boy and a 23-month-old girl undergoing alloHSCT for MPS VI and MPS IH Shanghai Children's Medical Center on March 30, 2006 and September 6, 2006 were selected as the study subjects. A busulfan-based myeloablative regimen was used as the conditioning regimen. Peripheral stem cells were respectively collected from a human leucocyte antigen (HLA) matched sibling carrier donor and a HLA 9/10 matched unrelated donor. Both patients were followed up for more than 15 years. The functions of internal organs before and after the transplantation were compared, and child 1 was also compared with his untreated brother and healthy brother. Both children have achieved full donor chimerism after the transplantation, and their enzymatic activities have remained stable. The enzymatic activity of the child 1 was slightly lower than normal but similar to that of his carrier donor, whilst that of the child 2 was normal. Both children have attended schools with good academic performance. Compared with his untreated brother, the respiratory function and hearing of child 1 have significantly improved. However, his orthopedic and cardiac disorders have still remained and required medical intervention. For child 2, her obstructive pulmonary disease was resolved and cognitive development was well preserved after the HSCT. Her heart disease has become stabilized and even improved with time, though her corneal clouding and skeletal malformation still required surgery. MPS patients can sustain long-term and stable enzymatic activities after successful alloHSCT. Compared with untreated patients, their health can be significantly improved, along with considerably prolonged survival, though the long-term efficacy of HSCT for different organs may vary to a certain extent.

Abstract LB_C21: Exogenous N-acetylgalactosamine-4-sulfatase (ARSB)-mediated tumor suppression involves effects on chondroitin 4-sulfate binding with SHP-2 and galectin-3, MAPK signaling, and transcriptional events, including epigenetic regulation of PD-L1

Abstract In experiments in melanoma, prostate, colon, and mammary cells and tissues, the enzyme N-acetylgalactosamine-4-sulfatase (Arylsulfatase B: ARSB), which removes the 4-sulfate group at the non-reducing end of chondroitin 4-sulfate (C4S), acts as a tumor suppressor. Following treatment with recombinant human (rh) ARSB in previous experiments and in recent experiments in the B16F10 mouse model of malignant melanoma, specific molecular pathways have been identified that retard tumor progression. These pathways involve more or less binding with chondroitin 4-sulfate when ARSB activity is modified. Galectin-3 binding with C4S increases following exogenous ARSB, leading to lower nuclear galectin-3 and reduced expression of chondroitin sulfate proteoglycan (CSPG)4 and of carbohydrate sulfotransferase (CHST)15 in melanoma cells and tissues. Nuclear Sp1 also declines, inhibiting transcription of both CSPG4, also known as the melanoma-associated chondroitin sulfate proteoglycan (MCSP), and of CHST15, which is required for 6-sulfation of N-acetylgalactosamine 4-sulfate. These proteins are associated with more aggressive tumors, and decline in their expression is consistent with the tumor suppressive function of ARSB. Inverse to the effect on galectin-3, SHP2, the ubiquitous non-receptor tyrosine phosphatase (PTPN11), binds less to C4S following treatment with exogenous ARSB. The resulting activation of SHP2 impacts on MAPK signaling, reducing phospho-ERK1/2 and phospho(T180/Y182)-p38-MAPK. These effects lead to decline in expression of the matrix metalloproteinases MMP2 and MMP9 and thereby restrain invasiveness and metastasis. Treatment of cultured melanoma cells with siRNA for ARSB leads to opposite effects to those of exogenous ARSB, including epigenetic effects modifying Programmed Death-Ligand 1 (PD-L1) expression. Treatment with rhARSB significantly reduces PD-L1 protein and gene expression, in contrast to increases when ARSB is silenced. The effects of rhARSB on PD-L1 expression are attributable to declines in phospho-JNK and nuclear c-Jun when free galectin-3 is less and to associated increases in histone deacetylase (HDAC) 3 expression and activity. Consistent with these effects, the ARSB-silencing induced increase in PD-L1 is inhibited by peptide inhibitors of the JNK-c-Jun interaction and by HDAC3 inhibitor. ARSB silencing reduces PD-L1 promoter acetylation, as shown by chromatin immunoprecipitation with anti-acetylhistone H3 antibody. The impact of rhARSB on signaling pathways, transcriptional events, and epigenetic mechanisms demonstrates how a critical sulfation and the resulting modification of chondroitin 4-sulfate can influence vital cell processes and can suppress tumor development. Effects on subcutaneous and pulmonary melanomas demonstrate the impact of exogenous ARSB in melanoma and suggest future prospects as a therapeutic agent. Recombinant human ARSB is an approved agent for the treatment of Mucopolysaccharidosis VI and is used safely and effectively for this congenital deficiency of ARSB. Citation Format: Joanne K. Tobacman, Insug O-Sullivan, Sumit Bhattacharyya. Exogenous N-acetylgalactosamine-4-sulfatase (ARSB)-mediated tumor suppression involves effects on chondroitin 4-sulfate binding with SHP-2 and galectin-3, MAPK signaling, and transcriptional events, including epigenetic regulation of PD-L1 [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr LB_C21.

Skeletal phenotype amelioration in Mucopolysaccharidosis VI requires intervention at the earliest stages of postnatal development.

Mucopolysaccharidosis VI (MPS VI) is a rare lysosomal disease arising from impaired function of the enzyme Arylsulfatase B (ARSB). This causes aberrant accumulation of dermatan sulfate, a glycosaminoglycan (GAG) abundant in cartilage. While clinical severity varies along with age at first symptom manifestation, MPS VI usually presents early and strongly affects the skeleton. Current enzyme replacement therapy (ERT) does not provide effective treatment for the skeletal manifestations of MPS VI. This lack of efficacy may be due to inability of ERT to reach affected cells, or irreversibility of disease. To address the question of reversibility of skeletal phenotypes, we generated a conditional by inversion (COIN) mouse model of MPS VI, ArsbCOIN/COIN, wherein Arsb is initially null and can be restored to wild type using Cre. We restored Arsb at different times during postnatal development, using a tamoxifen-dependent global Cre driver. By restoring Arsb at postnatal days 7, 21, and 56-70 (P7, P21, and P56-P70), we determined that skeletal phenotypes can be fully rescued if Arsb restoration occurs at P7, while only achieving partial rescue at P21, and no significant rescue at P56-70. This work has highlighted the importance of early intervention in MPS VI patients to maximize therapeutic impact.

Glycosaminoglycan-induced proinflammatory cytokine levels as disease marker in mucopolysaccharidosis

Recently, it has been shown disturbances in oxidant/antioxidant system and increases in some inflammatory markers in animal studies and in some Mucopolysaccharidoses (MPSs) patients. In this study, we aimed to determine the oxidative stress/antioxidant parameters and pro-inflammatory cytokine levels in the serum of MPS patients, in order to evaluate the possible role of inflammation in these patient groups regarding to accumulated metabolites.MPS I (n = 3), MPS II (n = 8), MPS III (n = 4), MPS IVA (n = 3), MPS VI (n = 3), and VII (n = 1) patients and 20 age-matched healthy subjects were included into the study.There was no statistically significant change in activities of SOD, Catalase, GSH-Px and lipid peroxidation levels in erythrocytes between the MPS patients and healthy controls. While IL-1alpha (p = 0.054), IL-6 (p = 0.008) levels, and chitotriosidase activity (p = 0.003) elevated in MPS3 patients, IL1α (p = 0.006), IL-1β (p = 0.006), IL-6 (p = 0.006), IFNγ (p = 0.006), and NFκB (p = 0.006) levels increased in MPS-6 patients.Elevated levels of IL-6, IL1α and chitotriosidase activity demonstrated macrophage activation in MPSIII untreated with enzyme replacement. Our study showed for the first time that high levels of IL1α, IL-6, IL1β and NFκB were present in MPSVI patients, demonstrating the induction of inflammation by dermatan sulphate. The low level of paraoxonase in MPSVI patients may be a good marker for cardiac involvement.Overall, this study provides important insights into the relationship between lysosomal storage of glycosaminoglycan and inflammation in MPS patients. It highlights possible pathways for the increased release of inflammatory molecules and suggests new targets for the development of treatments.

Help Comes from Unexpected Places: How a Tiny Fairy and a Tropical Fish may help us Model Mucopolysaccharidoses

Introduction:: When it comes to disease modeling, countless models are available for Lysosomal Storage Diseases (LSD). Historically, two major approaches are well-established: in vitro assessments are performed in patient fibroblasts, while in vivo pre-clinical studies are performed in mouse models. Still, both platforms have a series of drawbacks. Thus, we implemented two alternative and innovative protocols Methods:: The first one relies on a non-invasive approach using dental pulp stem cells from deciduous teeth (SHEDs). SHEDs are multipotent neuronal precursors that can easily be collected. The second uses a state-of-the-art gene editing technology (CRISPR/Cas9) to generate zebrafish disease models. Results:: Even though this is an ongoing project, we have already established and characterized two MPS II and one MPS VI SHED cell models. These cells self-maintain through several passages and can give rise to a variety of cells including neurons. Furthermore, all MPS-associated sub-cellular phenotypes we have assessed so far are easily observable in these cells. Regarding our zebrafish models, we have successfully knocked down both naglu and hgsnat and the first results we got from the behavioral analysis are promising ones, as we can observe altered activity and sleep patterns in the genetically modified fish. For this particular approach we chose MPS III forms as our target disorders, since their neurological features (hyperactivity, seizures and motor impairment) and lifespan decrease would be easily recognizable in zebrafish. Conclusion:: Now that these methods are well-established in our lab, their potential is immense. On one hand, the newly developed models will be of ultimate value to understand the mechanisms underlying MPS sub-cellular pathology, which have to be further elucidated. On the other hand, they will constitute an optimal platform for drug testing in house. Also noteworthy, our models will be published as lab resources and made available for the whole LSD community.

Reduction of lysosome abundance and GAG accumulation after odiparcil treatment in MPS I and MPS VI models

Deficiencies of lysosomal enzymes responsible for the degradation of glycosaminoglycans (GAG) cause pathologies commonly known as the mucopolysaccharidoses (MPS). Each type of MPS is caused by a deficiency in a specific GAG-degrading enzyme and is characterized by an accumulation of disease-specific GAG species. Previously, we have shown the potential of the beta-D-xyloside, odiparcil, as an oral GAG clearance therapy for Maroteaux-Lamy syndrome (MPS VI), an MPS characterized by an accumulation of chondroitin sulphate (CS) and dermatan sulphate (DS). This work suggested that odiparcil acts via diverting the synthesis of CS and DS into odiparcil-bound excretable GAG. Here, we investigated the effect of odiparcil on lysosomal abundance in fibroblasts from patients with MPS I and MPS VI. In MPS VI fibroblasts, odiparcil reduced the accumulation of a lysosomal-specific lysotracker dye. Interestingly, a reduction of the lysotracker dye was also observed in odiparcil-treated fibroblasts from patients with MPS I, a disorder characterized by an accumulation of DS and heparan sulphate (HS). Furthermore, odiparcil was shown to be effective in reducing CS, DS, and HS concentrations in liver and eye, as representative organs, in MPS VI and MPS I mice treated with 3 doses of odiparcil over 3 and 9 months, respectively. In conclusion, our data demonstrates odiparcil efficiently reduced lysosome abundance and tissue GAG concentrations in in vitro and in vivo models of MPS VI and MPS I and has potential as a treatment for these disorders.

The clinical and genotypic-phenotypic findings of mucopolysaccharidosis VI patients: an Iraqi single-study descriptive study.

Maroteaux-Lamy syndrome (mucopolysaccharidosis type VI; MPS VI) is a chronic illness that causes progressive enlargement, inflammation, or scarring of several tissues and organs until their collapse. In most cases, an infant with MPS VI shows no symptoms. The early signs and symptoms of MPS VI in children often develop in the first few months of life. MPS VI affects various systems in the body, including the skeletal, cardiac, and respiratory systems. The authors aim in our study to describe the clinical and genotypic-phenotypic findings of MPS VI patients in 'children Welfare Teaching Hospital, Medical City Complex.' The single-center study was conducted at the 'children Welfare Teaching Hospital, Medical City Complex' from November 2016 to May 2022. The research recruited 72 MPS VI patients from Iraq, all under 20. The authors investigated the sociodemographic characteristics, hematological lab results, gene-phenotype findings, and clinical features and evaluated the severity and progression of the MPS 6 disease. Seventy-two Iraqi MPS VI patients were involved in the study, and the average age of the study sample was 6.38±3.4 (0.3-19). The consanguinity rate was 94.4%. In the research, females comprised 56.9% of the patients, and the Z-scores for body mass index and occipital-frontal head circumference were -2.66 and 1.2. The fascial features at diagnosis, 'coarse facies' (90.3%), dysostosis multiplex (93%), short stature (94.4%), and recurrent respiratory infections (91.6%), were the most common clinical features among the enrolled patients. The most frequent mutation was (complementary DNA: c.753C>G, protein effect: p.(Tyr2*) or p.(Tyr251Term), and the codon cross-tabulation: premature stop codon, or homozygous stop nonsense mutation/exon N.3) (33/69 (47.82%)). Furthermore, a statistically significant correlation existed between lower weight and height readings and the progressed and severe stages of the MPS VI illness. As the first research in Iraq with a sufficient sample size of MPS VI patients, the investigation presented important clinical and gene-phenotype findings and revealed the necessity for enhancing the diagnosis of MPS VI, including the updated molecular analysis and monitoring the multisystem parameters, aberrant comorbidities, and the progression and severity.

Identification of genetic variants associated with a wide spectrum of phenotypes clinically diagnosed as Sanfilippo and Morquio syndromes using whole genome sequencing.

Mucopolysaccharidoses (MPSs) are inherited lysosomal storage disorders (LSDs). MPSs are caused by excessive accumulation of mucopolysaccharides due to missing or deficiency of enzymes required for the degradation of specific macromolecules. MPS I-IV, MPS VI, MPS VII, and MPS IX are sub-types of mucopolysaccharidoses. Among these, MPS III (also known as Sanfilippo) and MPS IV (Morquio) syndromes are lethal and prevalent sub-types. This study aimed to identify causal genetic variants in cases of MPS III and MPS IV and characterize genotype-phenotype relations in Pakistan. We performed clinical, biochemical and genetic analysis using Whole Genome Sequencing (WGS) in 14 Pakistani families affected with MPS III or MPS IV. Patients were classified into MPS III by history of aggressive behaviors, dementia, clear cornea and into MPS IV by short trunk, short stature, reversed ratio of upper segment to lower segment with a short upper segment. Data analysis and variant selections were made based on segregation analysis, examination of known MPS III and MPS IV genes, gene function, gene expression, the pathogenicity of variants based on ACMG guidelines and in silico analysis. In total, 58 individuals from 14 families were included in the present study. Six families were clinically diagnosed with MPS III and eight families with MPS IV. WGS revealed variants in MPS-associated genes including NAGLU, SGSH, GALNS, GNPTG as well as the genes VWA3B, BTD, and GNPTG which have not previously associated with MPS. One family had causal variants in both GALNS and BTD. Accurate and early diagnosis of MPS in children represents a helpful step for designing therapeutic strategies to protect different organs from permanent damage. In addition, pre-natal screening and identification of genetic etiology will facilitate genetic counselling of the affected families. Identification of novel causal MPS genes might help identifying new targeted therapies to treat LSDs.