PrP glycoforms are associated in a strain-specific ratio in native PrPSc

Area of Science:

• Neuroscience
• Biochemistry
• Molecular Biology

Background:

• Prion diseases are characterized by the conversion of cellular prion protein (PrPC) to a disease-associated isoform (PrPSc).
• Understanding the structural and molecular differences between PrPC and PrPSc is crucial for diagnosing and treating prion diseases.

Purpose of the Study:

• To generate and characterize monoclonal antibodies targeting specific epitopes of human prion protein (PrP).
• To investigate the structural exposure of PrP regions in native PrPSc from human and mouse prion diseases.
• To analyze the association and glycoform composition of PrP molecules in native PrPSc.

Main Methods:

• Production of monoclonal antibodies against recombinant human beta-PrP and alpha-PrP.
• Immunoprecipitation assays using these antibodies to isolate PrPC and PrPSc from normal and diseased brain tissues.
• Analysis of PrP glycoform ratios in immunoprecipitated PrPSc using Western blotting.

Main Results:

• Monoclonal antibodies recognized epitopes between residues 93-105, exposed in both human vCJD and mouse RML PrPSc.
• Antibodies to alpha-PrP preferentially immunoprecipitated PrPC and could distinguish between PrP glycoforms.
• Differentially glycosylated PrPSc molecules were found to be closely associated and immunoprecipitated together, with glycoform ratios consistent across prion strains.

Conclusions:

• The region 93-105 of PrP is exposed in native PrPSc, providing a potential diagnostic target.
• PrPSc particles contain a mixture of glycoforms, with their proportions likely controlled in a strain-specific manner.
• These findings offer insights into the structural heterogeneity and assembly of PrPSc in prion diseases.