Yeast-Produced Human Recombinant Lysosomal β-Hexosaminidase Efficiently Rescues GM2 Ganglioside Accumulation in Tay-Sachs Disease.

Background: Tay-Sachs disease (TSD) is an autosomal recessive lysosomal storage disorder characterized by the accumulation of GM2 ganglioside due to mutations in the HEXA gene, which encodes the α-subunit of β-Hexosaminidase A. This accumulation leads to significant neuropathological effects and premature death in affected individuals. No effective treatments exist, but enzyme replacement therapies are under investigation. In our previous work, we demonstrated the internalization and efficacy of human recombinant lysosomal β-hexosaminidase A (rhHex-A), produced in the methylotrophic yeast Pichia pastoris, in reducing lipids and lysosomal mass levels in fibroblasts and neural stem cells derived from patient-induced pluripotent stem cells (iPSCs). In this study, we further evaluated the potential of rhHex-A to prevent GM2 accumulation using fibroblast and neuroglia cells from a TSD patient alongside a relevant mouse model. Methods: Fibroblasts and neuroglial cell lines derived from a murine model and TSD patients were treated with 100 nM rhHexA for 72 h. After treatment, cells were stained by anti-GM2 (targeting GM2 ganglioside; KM966) and anti-LAMP1 (lysosomal-associated membrane protein 1) colocalization staining and incubated with 50 nM LysoTracker Red DND-99 to label lysosomes. In addition, GM2AP and HEXB expression were analyzed to assess whether rhHex-A treatment affected the levels of enzymes involved in GM2 ganglioside degradation. Results: Immunofluorescence staining for LysoTracker and colocalization studies of GM2 and Lamp1 indicated reduced lysosomal mass and GM2 levels. Notably, rhHex-A treatment also affected the expression of the HEXB gene, which is involved in GM2 ganglioside metabolism, highlighting a potential regulatory interaction within the metabolic pathway. Conclusions: Here, we report that rhHex-A produced in yeast can efficiently degrade GM2 ganglioside and rescue lysosomal accumulation in TSD cells.