Quantitative and Comparative Assessment of Recombinant Human β-Glucocerebrosidase Uptake Bioactivity Using a Stable...

Area of Science:

• Biochemistry
• Pharmacology
• Cell Biology

Background:

• Cellular uptake of recombinant human β-glucocerebrosidase (rhGCase) is crucial for Gaucher disease treatment.
• Existing methods lack reliability, hindering accurate potency comparisons of rhGCase products.

Purpose of the Study:

• To develop a robust bioassay for quantifying rhGCase cellular uptake.
• To enable accurate potency assessment and quality control of rhGCase therapeutics.

Main Methods:

• Utilized CHO-K1 cells engineered to express the human macrophage mannose receptor (hMMR).
• Quantified internalized rhGCase via enzymatic activity assays.
• Validated uptake specificity using mannose, fucose, and mannose-6-phosphate inhibition.

Main Results:

• The novel bioassay consistently generated sigmoidal dose-response curves.
• rhGCase uptake was confirmed to be hMMR-mediated and targeted to endosomes/lysosomes.
• Imiglucerase exhibited superior cellular uptake compared to velaglucerase alfa, contradicting previous findings.

Conclusions:

• The developed bioassay offers a more accurate and reproducible method for evaluating rhGCase cellular uptake bioactivity.
• This assay is essential for the quality control of rhGCase therapeutics for Gaucher disease.
• Findings necessitate a re-evaluation of rhGCase product potency and efficacy.