Arrayed CRISPR/Cas9 Loss-Of-Function Screen in a Neuronal Model of Adaptor Protein Complex 4 Deficiency Identifies...

Area of Science:

• Neuroscience
• Genetics
• Cell Biology

Background:

• Biallelic loss-of-function variants in adaptor protein complex 4 (AP-4) impair transmembrane protein trafficking.
• This disruption affects proteins like ATG9A at the trans-Golgi network, causing hereditary spastic paraplegia (AP-4-HSP).
• AP-4-HSP presents as both a neurodevelopmental and neurodegenerative condition.

Purpose of the Study:

• To elucidate the molecular mechanisms driving AP-4-HSP.
• To identify potential therapeutic targets for AP-4-HSP.
• To investigate the regulation of ATG9A trafficking in neuronal models.

Main Methods:

• An arrayed CRISPR/Cas9 loss-of-function screen of 8,478 genes was performed on a human neuronal model of AP-4 deficiency.
• Phenotypic screening identified genes modulating ATG9A trafficking.
• Pathway analyses were conducted to understand ATG9A transport regulation.

Main Results:

• Key modulators of ATG9A trafficking were identified through the CRISPR screen.
• Knockdown of ANPEP and NPM1 increased ATG9A availability outside the trans-Golgi network.
• These genes appear to regulate ATG9A localization within the cell.

Conclusions:

• The study deepens the understanding of ATG9A trafficking in AP-4 deficiency.
• ANPEP and NPM1 are identified as regulators of ATG9A localization.
• Findings provide a framework for developing targeted therapies for AP-4-HSP.