Differential expression of microRNAs from miR-17 family in the cerebellum of mucopolysaccharidosis type I mice.

Mucopolysaccharidosis type I (MPS I) is caused by deficiency of α-l-iduronidase, involved in degradation of glycosaminoglycans. Clinical manifestations are widely variable and patients with severe phenotype present developmental delay and cognitive decline, among other systemic alterations. MPS I patients present secondary accumulation of gangliosides in neuronal cells, besides accumulation of undegraded glycosaminoglycans. Reduction of Neu1 expression has been previously observed in the cerebellum of MPS I mice; to be active, neuraminidase 1 forms the lysosomal multienzyme complex (LMC) with two other proteins, ß-galactosidase and protective protein/cathepsin A, involved in stepwise degradation of gangliosides in the lysosomes. In this study, we evaluated relative expression of LMC genes and six possible regulators of their expression, microRNAs (miRNAs) from miR-17 family, which are predicted to target at least two LMC components, in the cerebellum of MPS I mice by real-time PCR. Neu1 was significantly underexpressed in MPS I mice cerebellum, whereas expression of other LMC genes was similar to controls. miR-20b and miR-106b were differentially expressed in MPS I mice, suggesting that they may be involved in the reduction of Neu1 expression; miR-20b-5p was overexpressed while miR-20b-3p and miR-106b-5p were underexpressed. The ratio between miR-20b-3p and miR-20b-5p was also altered in cerebellum of MPS I mice. Confirmation of binding predictions and analysis of the direct role of these miRNAs in the regulation of Neu1 expression could bring important information regarding LMC function. Since miRNAs from miR-17 family are involved in regulation of diverse biological processes, our results also point to new pathogenic cascades to be investigated in MPS I.

Characteristics of free endoglucanase and glycosidases multienzyme complex from Fusarium verticillioides.

A novel multienzyme complex, E1C, and a free endoglucanase, E2 (GH5), from Fusarium verticillioides were purified. The E1C contained two endoglucanases (GH6 and GH10), one cellobiohydrolase (GH7) and one xylanase (GH10). Maximum activity was observed at 80 °C for both enzymes and they were thermostable at 50 and 60 °C. The activation energies for E1C and E2 were 21.3 and 27.5 kJ/mol, respectively. The KM for E1C was 10.25 g/L while for E2 was 6.58 g/L. Both E1C and E2 were activated by Mn(2+) and CoCl2 while they were inhibited by SDS, CuSO4, FeCl3, AgNO4, ZnSO4 and HgCl2. E1C and E2 presented endo-ß-1,3-1,4-glucanase activity. E1C presented crescent activity towards cellopentaose, cellotetraose and cellotriose. E2 hydrolyzed the substrates cellopentaose, cellotetraose and cellotriose with the same efficiency. E1C showed a higher stability and a better hydrolysis performance than E2, suggesting advantages resulting from the physical interaction between proteins.