Murine cellular model of mucopolysaccharidosis, type IIIB (MPS IIIB) - A preliminary study with particular emphasis on the non-oxidative l-cysteine metabolism.

The lack of the N-alpha-glucosaminidase (Naglu) is responsible for the incidence of a rare disease - mucopolysaccharidosis, type IIIB (MPS IIIB). To date, studies have been conducted based on cells derived from patients suffering from MPS or using in vivo MPS mouse models. These limitations have allowed for defining our research goal - to create and characterize the first in vitro murine cellular MPS IIIB model. In the current work we present a new, stable cell line with confirmed accumulation of glycosaminoglycans. The line stability was achieved by immortalization using a lentivirus carrying the T-antigens of SV40. The Naglu-/- cells were confirmed to produce no Naglu enzyme. To confirm the proper functioning of the in vitro MPS IIIB model, we determined the activity and expression of cystathionine γ-lyase, rhodanese and 3-mercaptopyruvate sulfurtransferase, as well as the level of low molecular-weight thiols (reduced and oxidized glutathione, cysteine and cystine). The results were referred to our earlier findings originating from the studies on the tissues of the Naglu-/- mice that were used to create the lines. The results obtained in the Naglu-/- cells were in accordance with the results found in the mouse model of MPS IIIB. It suggests that the presented murine Naglu-/- cell lines might be a convenient in vitro model of MPS IIIB.

Effect of glycosaminoglycans accumulation on the non-oxidative sulfur metabolism in mouse model of Sanfilippo syndrome, type B.

Lack of the N-alpha-acetylglucosaminidase gene is responsible for the occurrence of a rare disease - the Sanfilippo syndrome, type B. The result of this gene knock-out is accumulation of glycosaminoglycans (GAGs) - more specifically heparan sulfate - a sulfate rich macromolecule. The sulfur oxidative pathway is involved in the sulfate groups' turnover in the cells. In contrast, the non-oxidative sulfur pathway leads mostly to formation of sulfane sulfur-containing compounds. The aim of our research was to observe an interaction between MPS IIIB and non-oxidative sulfur metabolism. In this work, we examined selected tissues (livers, kidneys, hearts and spleens) of 3 month old mice with confirmed accumulation of GAGs. The activity and expression of three sulfurtransferases (components of non-oxidative sulfur metabolism): rhodanese, 3-mercaptopyruvate sulfurtransferase and cystathionine γ-lyase was determined, as well as the sulfane sulfur level and the level of other low molecular sulfur-containing compounds (reduced and oxidized glutathione, cysteine and cystine). In all tested tissues, the sulfane sulfur and/or sulfurtransferases' activities, as well as the cysteine content, underwent statistically significant changes. These correlations were also related to the sex of the tested animals. The obtained results indicated that accumulation of incompletely degraded GAGs in the tissues had affected the non-oxidative sulfur metabolism.