Characterization of Cellular Alterations in a Novel NAGLU Enzyme-Deficient Cellular Model Generated from U-87MG Cell Line.

Mucopolysaccharidosis IIIB (MPS IIIB) is an inherited metabolic disorder caused by mutations in NAGLU gene, resulting in the accumulation of heparan sulphate in lysosomes and cell membranes. This accumulation leads to cellular dysfunction, apoptosis, tissue damage, and organ failure. MPS IIIB is considered a neurodegenerative disease that causes motor impairment, developmental delay, sleep disturbance, and dementia. This is usually diagnosed around 3-4 years of age with an incidence of 1 per 200,000 live births. Current research focuses on cellular defects in the central nervous system, particularly in neurons. Conversely, the effects on glial cell types, such as microglia and astrocytes, which play a key role in brain homeostasis, remain unknown. Currently, there is not any glial cell model that allows us to assess different therapeutic strategies. In this study, we generated a glial cell model deficient in the NAGLU enzyme via CRISPR/Cas9 editing system in the U-87MG cell line. Characterization of this cellular model exhibited typical traits for MPS IIIB, including decreased enzyme activity and mitochondrial mass, as well as increased lysosomal mass, neutral lipids, total glycosaminoglycans, and total reactive oxygen species, along with an altered autophagy flux. Thus, it is expected that this model will contribute to the development and assessment of therapeutic strategies, as well as a better understanding of the molecular and cellular basis of MPS IIIB.