Early Diagnosis and Results of Enzyme Replacement Therapy in the Patient with Mucopolysaccharidosis Type VI: Clinical Case

Background. Mucopolysaccharidosis type VI (MPS VI, Maroteaux–Lamy syndrome) is rare autosomal-recessive multisystem disease, one of the group of lysosomal storage diseases. The MPS VI pathogenesis is determined by arylsulfatase B enzyme deficiency caused by mutations in the ARSB gene. There are only few published clinical examples of this disease that covers the results of early enzyme replacement therapy (ERT) onset.Clinical case description. The child was suspected to have lysosomal storage disease at the age of 1.5 months, it was based on microscopic analysis of blood smears: Alder abnormality was revealed (granulations and red-violet inclusions in neutrophils, monocytes, lymphocytes cytoplasm). The diagnosis was confirmed at the age of 3 months: increased glycosaminoglycans (GAGs) concentration in the urine, arylsulfatase B activity decrease in dried blood spots, and pathogenic variant c.943C>T (p. R315X) in the ARSB gene in homozygous state were revealed. ERT with galsulfase was started at the age of 7 months. There was decrease in excretion of GAGs in urine to normal level after 9 and 15 months of therapy. Normal growth and body proportions for the patient’s age were determined 3 years after continuous ERT. However, there was progression of multiple dysostosis and joint stiffness, as well as eyes lesion.Conclusion. Early ERT onset cannot completely stop MPS VI progression but it allows to reduce the severity of several symptoms and improves patient’s quality of life.

Mucopolysaccharidosis Type VI, an Updated Overview of the Disease

Mucopolysaccharidosis type VI, or Maroteaux–Lamy syndrome, is a rare, autosomal recessive genetic disease, mainly affecting the pediatric age group. The disease is due to pathogenic variants of the ARSB gene, coding for the lysosomal hydrolase N-acetylgalactosamine 4-sulfatase (arylsulfatase B, ASB). The enzyme deficit causes a pathological accumulation of the undegraded glycosaminoglycans dermatan-sulphate and chondroitin-sulphate, natural substrates of ASB activity. Intracellular and extracellular deposits progressively take to a pathological scenario, often severe, involving most organ-systems and generally starting from the osteoarticular apparatus. Neurocognitive and behavioral abilities, commonly described as maintained, have been actually investigated by few studies. The disease, first described in 1963, has a reported prevalence between 0.36 and 1.3 per 100,000 live births across the continents. With this paper, we wish to contribute an updated overview of the disease from the clinical, diagnostic, and therapeutic sides. The numerous in vitro and in vivo preclinical studies conducted in the last 10–15 years to dissect the disease pathogenesis, the efficacy of the available therapeutic treatment (enzyme replacement therapy), as well as new therapies under study are here described. This review also highlights the need to identify new disease biomarkers, potentially speeding up the diagnostic process and the monitoring of therapeutic efficacy.

Expanding the understanding of viral tropism by characterizing the N-glycomic profiles of transducible cell lines and tissue types and Characterizing functional receptors that mediate the inhibitory relationship between 4-O-sulfated chondroitin sulfate and neurons

1: Glycosylation plays an important role in facilitating viral transduction by acting as preliminary cell surface receptors. For this reason, the structural determinants in glycans that dictate viral tissue tropism need to be extensively studied to improve the efficacy of gene therapy vectors in basic research and eventually the clinic. Elucidating the dependencies for viral transduction initiation and understanding how these structural nuances of glycans initiate virion specific tropic effects is paramount when considering how to use vectors to improve clinical outcomes for patients suffering from illnesses with few treatment options. The goal of this project was to use MALDI-TOF-MS to provide baseline N-glycan profiles of the cell lines and tissues used to test gene therapy vectors. In doing so these profiles will be valuable to the field by clarifying what structural determinants may influence viral tropism. It was discovered Neu5Ac sialic acid content differs qualitatively amongst the seven cell lines analyzed. These differences may play into why some cell lines such as CHO-K1 and COS-7 can transduce more preferentially with some AAV serotypes like AAV5. In addition, sialic acid differences were also assessed in three tissue types used in transduction assays. Abstract 2: After injury to the CNS, reactive astrocytes form a protective extracellular matrix to isolate damaged tissue. These astrocytes influence the surrounding tissue by upregulating the production of proteoglycans containing chondroitin sulfate. Due to the new cellular environment, chondroitin sulfate (CS) glycosaminoglycan chains are upregulated with predominately 4-O-sulated sulfation patterns. These sulfation patterns are known to inhibit axonal guidance, and ultimately neuronal regeneration. While the inhibitory effect of CS is well known, the mechanism by which these specific sulfation patterns may interact with receptors also known to have inhibitory effects on neuro-regeneration such as protein tyrosine phosphatase σ is unknown. To characterize these interactions reductive amination was used to immobilize these CS chains onto solid beads. Chondroitin sulfate was isolated from the organs of an ARSB null mouse model which lacks the N-acetylgalactosamine-4-sulfatase (arylsulfatase B, ARSB) which is involved in the degradation of glycosaminoglycans (GAGs). Disruption of arylsulfatase B leads to the production of CS chains with 4-O-sulfated non-reducing ends exclusively. Key findings indicate that purified GAG chains retain their ligand specificity after being covalently immobilized onto solid supports, and that these systems can be utilized to characterize the relationship between inhibitory forms of CS and protein tyrosine phosphatase σ.

Increase in Chondroitin Sulfate and Decline in Arylsulfatase B May Contribute to Pathophysiology of COVID-19 Respiratory Failure

<b><i>Introduction:</i></b> The potential role of accumulation of chondroitin sulfates (CSs) in the pathobiology of COVID-19 has not been examined. Accumulation may occur by increased synthesis or by decline in activity of the enzyme arylsulfatase B (ARSB; N-acetylgalactosamine-4-sulfatase) which requires oxygen for activity. <b><i>Methods:</i></b> Immunostaining of lung tissue from 28 patients who died due to COVID-19 infection was performed for CS, ARSB, and carbohydrate sulfotransferase (CHST)15. Measurements of mRNA expression of CHST15 and CHST11, sulfotransferase activity, and total sulfated glycosaminoglycans (GAGs) were determined in human vascular smooth muscle cells following angiotensin (Ang) II treatment. <b><i>Results:</i></b> CS immunostaining showed increase in intensity and distribution, and immunostaining of ARSB was diminished in COVID-19 compared to normal lung tissue. CHST15 immunostaining was prominent in vascular smooth muscle cells associated with diffuse alveolar damage due to COVID-19 or other causes. Expression of CHST15 and CHST11 which are required for synthesis of CSE and chondroitin 4-sulfate, total sulfated GAGs, and sulfotransferase activity was significantly increased following AngII exposure in vascular smooth muscle cells. Expression of Interleukin-6 (IL-6), a mediator of cytokine storm in COVID-19, was inversely associated with ARSB expression. <b><i>Discussion/Conclusion:</i></b> Decline in ARSB and resulting increases in CS may contribute to the pathobiology of COVID-19, as IL-6 does. Increased expression of CHSTs following activation of Ang-converting enzyme 2 may lead to buildup of CSs.

Compound heterozygous missense mutations in a Chinese mucopolysaccharidosis type VI patient: a case report

Background Mucopolysaccharidosis type VI (MPS VI) is a rare autosomal recessive inherited disease caused by mutations in the arylsulfatase B (ARSB) gene. MPS VI is a multisystemic disease resulting from a deficiency in arylsulfatase B causing an accumulation of glycosaminoglycans in the tissues and organs of the body. In this report, we present the case of a 16-year-old Chinese male who presented with vision loss caused by corneal opacity. MPS VI was confirmed by genetic diagnosis. Case presentation A 16-year-old Chinese male presented with a one-year history of binocular vision loss. The best-corrected visual acuity was 0.25 in the right eye and 0.5 in the left eye. Although slit-lamp examination revealed corneal opacification in both eyes, the ocular examinations of his parents were normal. At the same time, the patient presented with kyphotic deformity, short stature, joint and skeletal malformation, thick lips, long fingers, and coarse facial features. Genetic assessments revealed that ARSB was the causative gene. Compound heterozygous missense mutations were found in the ARSB gene, namely c.1325G > A (p. Thr442Met) (M1) and c.1197G > C (p. Phe399Leu) (M2). Genetic diagnosis confirmed that the patient had MPS VI. Conclusions This paper reports a case of MPS VI confirmed by genetic diagnosis. MPS VI is a multisystem metabolic disease, with corneal opacity as a concomitant ocular symptom. As it is difficult for ophthalmologists to definitively diagnose MPS VI, genetic testing is useful for disease confirmation.

Specific Antiproliferative Properties of Proteinaceous Toxin Secretions from the Marine Annelid Eulalia sp. onto Ovarian Cancer Cells

As Yondelis joins the ranks of approved anti-cancer drugs, the benefit from exploring the oceans’ biodiversity becomes clear. From marine toxins, relevant bioproducts can be obtained due to their potential to interfere with specific pathways. We explored the cytotoxicity of toxin-bearing secretions of the polychaete Eulalia onto a battery of normal and cancer human cell lines and discovered that the cocktail of proteins is more toxic towards an ovarian cancer cell line (A2780). The secretions’ main proteins were identified by proteomics and transcriptomics: 14-3-3 protein, Hsp70, Rab3, Arylsulfatase B and serine protease, the latter two being known toxins. This mixture of toxins induces cell-cycle arrest at G2/M phase after 3h exposure in A2780 cells and extrinsic programmed cell death. These findings indicate that partial re-activation of the G2/M checkpoint, which is inactivated in many cancer cells, can be partly reversed by the toxic mixture. Protein–protein interaction networks partake in two cytotoxic effects: cell-cycle arrest with a link to RAB3C and RAF1; and lytic activity of arylsulfatases. The discovery of both mechanisms indicates that venomous mixtures may affect proliferating cells in a specific manner, highlighting the cocktails’ potential in the fine-tuning of anti-cancer therapeutics targeting cell cycle and protein homeostasis.

A Possible Role for Arylsulfatase G in Dermatan Sulfate Metabolism

Perturbations of glycosaminoglycan metabolism lead to mucopolysaccharidoses (MPS)—lysosomal storage diseases. One type of MPS (type VI) is associated with a deficiency of arylsulfatase B (ARSB), for which we previously established a cellular model using pulmonary artery endothelial cells with a silenced ARSB gene. Here, we explored the effects of silencing the ARSB gene on the growth of human pulmonary artery smooth muscle cells in the presence of different concentrations of dermatan sulfate (DS). The viability of pulmonary artery smooth muscle cells with a silenced ARSB gene was stimulated by the dermatan sulfate. In contrast, the growth of pulmonary artery endothelial cells was not affected. As shown by microarray analysis, the expression of the arylsulfatase G (ARSG) in pulmonary artery smooth muscle cells increased after silencing the arylsulfatase B gene, but the expression of genes encoding other enzymes involved in the degradation of dermatan sulfate did not. The active site of arylsulfatase G closely resembles that of arylsulfatase B, as shown by molecular modeling. Together, these results lead us to propose that arylsulfatase G can take part in DS degradation; therefore, it can affect the functioning of the cells with a silenced arylsulfatase B gene.

Increased Expression of Chondroitin Sulfotransferases following AngII may Contribute to Pathophysiology Underlying Covid-19 Respiratory Failure: Impact may be Exacerbated by Decline in Arylsulfatase B Activity

The spike protein of SARS-CoV-2 binds to respiratory epithelium through the ACE2 receptor, an endogenous receptor for Angiotensin II (AngII). The mechanisms by which this viral infection leads to hypoxia and respiratory failure have not yet been elucidated. Interactions between the sulfated glycosaminoglycans heparin and heparan sulfate and the SARS-CoV-2 spike glycoprotein have been identified as participating in viral adherence and infectivity. In this brief report, we present data indicating that stimulation of vascular smooth muscle cells by AngII leads to increased expression of two chondroitin sulfotransferases (CHST11 and CHST15), which are required for the synthesis of the sulfated glycosaminoglycans chondroitin 4-sulfate (C4S) and chondroitin 4,6-disulfate (CSE). We suggest that increased expression of these chondroitin sulfotransferases and the ensuing production of chondroitin sulfates may contribute to viral adherence to bronchioalveolar cells and to the progression of respiratory disease in Covid-19. The enzyme Arylsulfatase B (ARSB; N-acetylgalactosamine-4-sulfatase), which removes 4-sulfate groups from the non-reducing end of chondroitin 4-sulfate residues, is required for degradation of C4S and CSE. In hypoxic conditions or following treatment with chloroquine, ARSB activity is reduced. Decline in ARSB can contribute to ongoing accumulation and airway obstruction by C4S and CSE. Decline in ARSB leads to increased expression of Interleukin(IL)-6 in human bronchial epithelial cells, and IL-6 is associated with cytokine storm in Covid-19. These findings indicate how chondroitin sulfates, chondroitin sulfotransferases, and chondroitin sulfatases may participate in the progression of hypoxic respiratory insufficiency in Covid-19 disease and suggest new therapeutic targets.