Mucopolysaccharidosis type II (MPS II) or Hunter syndrome is a lysosomal storage disease caused by mutations in the gene coding for iduronate-2-sulfatase (IDS). In healthy individuals, this lysosomal enzyme prevents accumulation of glycosaminoglycans in multiple organs. Current treatments for MPS II are unable to alleviate neurological symptoms because of inefficient delivery of drugs into the brain. Gleitz et al. designed a brain-targeting approach that allowed IDS transport across blood-brain barrier. A chimeric protein LV.IDS.ApoEII was developed and contained the IDS fused to a flexible linker and tandem repeats of the human apolipoprotein E (ApoE) fragment for brain-targeting. The system was tested in rodents and resulted in complete correction of working memory deficits, neuroinflammation, heparan sulfate storage in the brain and other MPS II disease markers. The enzymatic activity of the iduronate-2-sulfatase (IDS) was assayed with fluorescent substrate 4MU-alpha-L-iduronide-2-sulphate (MU-αIdoA-2S) from Carbosynth and the fluorescence was measured at Ex360/Em460.
For more details, read the original paper published in EMBO Molecular Medicine: Gleitz et al., 2018.