# Genome-wide screens identify core regulators of cell surface prion protein expression

## TL;DR

This study identifies genes that control prion protein expression on neurons, which could lead to new treatments for prion and neurodegenerative diseases.

## Contribution

The study identifies core and state-specific regulators of prion protein expression in neuronal cells using genome-wide CRISPR screens.

## Key findings

- 46 positive and 21 negative regulators of cell surface PrPC were identified in undifferentiated CAD5 cells.
- 23 core genes regulating PrPC expression were shared between undifferentiated and differentiated CAD5 cells.
- Unique regulators were found in each cell state, indicating cell state-dependent mechanisms for PrPC expression.

## Abstract

Expression of the cellular prion protein, PrPC, on the surface of neurons plays an important role in the pathogenesis of prion disease. We performed genome-wide CRISPR/Cas9 knockout screens in prion-infectible cells of neuronal origin (CAD5) to identify regulators of cell surface PrPC expression. We identified and validated 46 positive and 21 negative regulators of cell surface PrPC expression in undifferentiated CAD5 cells. Pathway analysis of the screening dataset showed that genes involved in the glycophosphatidylinositol (GPI) anchor and N-glycosylation biosynthetic pathways were overrepresented as positive regulators of cell surface PrPC. We also sought to determine whether the same or different genes regulate cell surface PrPC in CAD5 cells that have been differentiated to a more neuronal state and validated 41 positive and 13 negative regulators of CAD5 cell surface PrPC expression in the differentiated state. We identified 23 core genes as shared between the undifferentiated and differentiated cell states, including many positive regulators involved in GPI anchor biosynthesis. Intriguingly, unique regulators were also identified in the undifferentiated and differentiated cell states, suggesting that some mechanisms regulating cell surface PrPC expression in CAD5 cells are dependent on cell state. This list of core genes involved in regulating cell surface PrPC expression in a prion-susceptible, neuron-like cell type offers a valuable guide for future research and may help identify potential therapeutic targets for prion disease and other neurodegenerative diseases.

The online version contains supplementary material available at 10.1038/s41598-026-37137-2.