A novel conditional Sgsh knockout mouse model recapitulates phenotypic and neuropathic deficits of Sanfilippo syndrome

AbstractMucopolysaccharidosis (MPS) type IIIA, or Sanfilippo syndrome, is a neurodegenerative lysosomal storage disorder caused by a deficiency of the lysosomal enzymeN-sulfoglucosamine sulfohydrolase (SGSH), involved in the catabolism of heparan sulfate. The clinical spectrum is broad and the age of symptom onset and the degree of preservation of cognitive and motor functions appears greatly influenced by genotype. To explore this further, we generated a conditional knockout (SgshKO) mouse model with ubiquitousSgsh deletion, and compared the clinical and pathological phenotype with that of the spontaneousSgshD31N MPS-IIIA mouse model. Phenotypic deficits were noted inSgshKO mice prior toSgshD31N mice, however these outcomes did not correlate with any shift in the time of appearance nor rate of accumulation of primary (heparan sulfate) or secondary substrates (GM2/GM3 gangliosides). Other disease lesions (elevations in lysosomal integral membrane protein-II expression, reactive astrocytosis and appearance of ubiquitin-positive inclusions) were also comparable between affected mouse strains. This suggests that gross substrate storage and these neuropathological markers are neither primary determinants, nor good biomarkers/indicators of symptom generation, confirming similar observations made recently in MPS-IIIA patients. TheSgshKO mouse will be a useful tool for elucidation of the neurological basis of disease and assessment of the clinical efficacy of new treatments for Sanf...
Source: Journal of Inherited Metabolic Disease - Category: Internal Medicine Source Type: research