Recombinant caprine 3H-[N-acetylglucosamine-6-sulfatase] and human 3H-[N-acetylgalactosamine-4-sulfatase]: plasma clearance, tissue distribution, and cellular uptake in the rat

Exogenous recombinant N-acetylgalactosamine-4-sulfatase (Arylsulfatase B; ARSB) inhibits progression of B16F10 cutaneous melanomas and modulates cell signaling

In the syngeneic, subcutaneous B16F10 mouse model of malignant melanoma, treatment with exogenous ARSB markedly reduced tumor size and extended survival. In vivo experiments showed that local treatment with exogenous N-acetylgalactosamine-4-sulfatase (Arylsulfatase B; ARSB) led to reduced tumor growth over time (p < 0.0001) and improved the probability of survival up to 21 days (p = 0.0391). Tumor tissue from the treated mice had lower chondroitin 4-sulfate (C4S) content and lower sulfotransferase activity. The free galectin-3 declined, and the SHP2 activity increased, due to altered binding with chondroitin 4-sulfate. These changes induced effects on transcription, which were mediated by Sp1, phospho-ERK1/2, and phospho-p38 MAPK. Reduced mRNA expression of chondroitin sulfate proteoglycan 4 (CSPG4), carbohydrate sulfotransferase 15 (N-acetylgalactosamine 4-sulfate 6-O-sulfotransferase), and matrix metalloproteinases 2 and 9 resulted. Experiments in the human melanoma cell line A375 demonstrated similar responses to exogenous ARSB as in the tumors, and inverse effects followed ARSB siRNA. ARSB, which removes the 4-sulfate group at the non-reducing end of C4S, acts as a tumor suppressor, and treatment with exogenous ARSB impacts on vital cell signaling and reduces the expression of critical genes associated with melanoma progression.

Umbilical mesenchymal stem cell-derived extracellular vesicles as enzyme delivery vehicle to treat Morquio A fibroblasts

BACKGROUND

Mucopolysaccharidosis IVA (Morquio A syndrome) is a lysosomal storage disease caused by the deficiency of enzyme N-acetylgalactosamine-6-sulfate sulfatase (GALNS), which results in the accumulation of the glycosaminoglycans (GAGs), keratan sulfate, and chondroitin-6-sulfate in the lysosomes of all tissues causing systemic dysfunction. Current treatments include enzyme replacement therapy (ERT) which can treat only certain aspects of the disease such as endurance-related biological endpoints. A key challenge in ERT is ineffective enzyme uptake in avascular tissues, which makes the treatment of the corneal, cartilage, and heart valvular tissue difficult. The aim of this study was to culture human umbilical mesenchymal stem cells (UMSC), demonstrate presence of GALNS enzyme activity within the extracellular vesicles (EVs) derived from these UMSC, and study how these secreted EVs are taken up by GALNS-deficient cells and used by the deficient cell's lysosomes.

METHODS

We obtained and cultured UMSC from the umbilical cord tissue from anonymous donors from the Saint Louis Cord Blood Bank. We characterized UMSC cell surface markers to confirm phenotype by cell sorting analyses. In addition, we confirmed that UMSC secrete GALNS enzyme creating conditioned media for co-culture experiments with GALNS deficient cells. Lastly, we isolated EVs derived from UMSC by ultracentrifugation to confirm source of GALNS enzyme.

RESULTS

Co-culture and confocal microscopy experiments indicated that the lysosomal content from UMSC migrated to deficient cells as evidenced by the peak signal intensity occurring at 15 min. EVs released by UMSC were characterized indicating that the EVs contained the active GALNS enzyme. Uptake of GALNS within EVs by deficient fibroblasts was not affected by mannose-6-phosphate (M6P) inhibition, suggesting that EV uptake by these fibroblasts is gradual and might be mediated by a different means than the M6P receptor.

CONCLUSIONS

UMSC can deliver EVs containing functional GALNS enzyme to deficient cells. This enzyme delivery method, which was unaffected by M6P inhibition, can function as a novel technique for reducing GAG accumulation in cells in avascular tissues, thereby providing a potential treatment option for Morquio A syndrome.

Different serum enzyme levels are required to rescue the various systemic features of the mucopolysaccharidoses

Mucopolysaccharidoses (MPSs) are lysosomal storage disorders characterized by progressive accumulation of glycosaminoglycans (GAGs) in various tissues. Enzyme replacement therapy (ERT) for several MPSs is available to date. However, the efficacy of ERT is limited, in particular in compartments such as bone, cartilage, the brain, and the eyes. We selected a rodent model of an MPS, with no central nervous system storage, to study the impact, on systemic features of the disease, of various stable levels of exogenous enzymes produced by adeno-associated viral vector (AAV)-mediated liver gene transfer. Low levels (6% of normal) of circulating enzyme were enough to reduce storage and inflammation in the visceral organs and to ameliorate skull abnormalities; intermediate levels (11% of normal) were required to reduce urinary GAG excretion; and high levels (>or=50% of normal) rescued abnormalities of the long bones and motor activity. These data will be instrumental to design appropriate clinical protocols based on either enzyme or gene replacement therapy for MPS and to predict their impact on the pathological features of MPS.

Lentiviral-mediated correction of MPS VI cells and gene transfer to joint tissues

Joint disease in mucopolysaccharidosis type VI (MPS VI) remains difficult to treat despite the success of enzyme replacement therapy in treating other symptoms. In this study, the efficacy of a lentiviral vector to transduce joint tissues and express N-acetylgalactosamine-4-sulphatase (4S), the enzyme deficient in MPS VI, was evaluated in vitro and the expression of beta-galactosidase was used to evaluate transduction in vivo. High viral copy number was achieved in MPS VI fibroblasts and 4-sulphatase activity reached 12 times the normal level. Storage of accumulated glycosaminoglycan was reduced in a dose dependent manner in both MPS VI skin fibroblasts and chondrocytes. Enzyme expression was maintained in skin fibroblasts for up to 41 days. Comparison of two promoters; the murine phosphoglycerate kinase gene promoter (pgk) and the myeloproliferative sarcoma virus long terminal repeat promoter (mpsv), demonstrated a higher level of marker gene expression driven by the mpsv promoter in both chondrocytes and synoviocytes in vitro. When injected into the rat knee, the expression of beta-galactosidase from the mpsv promoter was widespread across the synovial membrane and the fascia covering the cruciate ligaments and meniscus. No transduction of chondrocytes or ligament cells was observed. Transduction was maintained for at least 8 weeks after injection. These results indicate that the lentiviral vector can be used to deliver 4S to a range of joint tissues in vitro and efficiently transduce synovial cells and express beta-galactosidase in vivo.

Inhibition of glycosaminoglycan synthesis using rhodamine B in a mouse model of mucopolysaccharidosis type IIIA

Reduction of an enzyme activity required for the lysosomal degradation of glycosaminoglycan (gag) chains will result in a mucopolysaccharidosis (MPS) disorder. Substrate deprivation therapy (SDT), a potential therapy option for MPS with residual enzyme activity, aims to reduce the synthesis of gag chains, the natural substrate for the deficient enzyme. Reduced substrate levels would balance the reduced level of enzyme in patient cells, resulting in normalized gag turnover. Rhodamine B, a nonspecific inhibitor, reduced gag synthesis in a range of normal and MPS cells and also decreased lysosomal storage of gag in MPS VI (72%) and MPS IIIA (60%) cells. Body weight gain of male MPS IIIA mice treated with 1 mg/kg rhodamine B was reduced compared with untreated MPS IIIA mice and was indistinguishable from that of normal mice. Liver size, total gag content, and lysosomal gag was reduced in treated MPS IIIA animals as was urinary gag excretion. Lysosomal gag content in the brain was also reduced by treatment. The alteration in MPS IIIA clinical pathology by rhodamine B, combined with the observation that treatment had no effect on the health of normal animals, demonstrates the potential for SDT in general as a therapy for MPS disorders.

Enzyme replacement therapy in a feline model of MPS VI: modification of enzyme structure and dose frequency

Enzyme replacement therapy (ERT) in the MPS VI cat is effective at reducing or eliminating pathology in most connective tissues. One exception is that cartilage and chondrocytes remained distended with extensive lysosomal vacuolation after long-term, high-dose ERT. In this study, we demonstrate that recombinant human N-acetylgalactosamine-4-sulphatase (4S) is taken up by chondrocytes via a mannose-6-phosphate-dependent mechanism and is effective at removing MPS storage. In vitro, the penetration of 4S into articular cartilage is low (partitioning coefficient = 0.06) and i.v. administered enzyme does not distribute significantly into articular cartilage in vivo. To alter the tissue distribution of 4S, the enzyme was coupled to ethylene diamine or poly-L-lysine, increasing its overall charge and diffusion into cartilage, and the dosing frequency of unmodified 4S was increased. Modification resulted in active 4S that maintained its ability to correct MPS storage and increased the partitioning coefficient of 4S into cartilage by 77% and 50% for ethylene diamine and poly-L-lysine, respectively. However, in vivo ERT studies demonstrated that response to therapy was not significantly improved by either the enzyme modifications or change to the dosing regimen, when compared with ERT with unmodified enzyme. Distribution experiments indicated the majority of enzyme is taken up by the liver irrespective of modification. To optimize therapy and improve the amount of enzyme reaching cartilage and other tissues demonstrating poor uptake, it may be necessary to bypass the liver or prolong plasma half-life so that proportionately more enzyme is delivered to other tissues.