Loss of Proteostasis Is a Pathomechanism in Cockayne Syndrome

Area of Science:

• Molecular Biology
• Cellular Biology
• Genetics

Background:

• Cockayne syndrome (CS) is a premature aging disease characterized by growth retardation and neurodegeneration.
• CS proteins are crucial for ribosomal biogenesis and RNA polymerase I transcription.
• A key aspect of CS pathogenesis involves disruptions in protein homeostasis (proteostasis).

Purpose of the Study:

• To elucidate the molecular mechanism linking RNA polymerase I transcription defects to protein misfolding in Cockayne syndrome.
• To investigate the role of reactive oxygen species (ROS) and the unfolded protein response (UPR) in CS pathogenesis.
• To explore potential therapeutic interventions for Cockayne syndrome.

Main Methods:

• Analysis of RNA polymerase I transcription in CS patient cells.
• Assessment of ribosomal function and translational fidelity.
• Measurement of reactive oxygen species (ROS) levels and unfolded protein response (UPR) activation.
• Evaluation of pharmacological chaperone treatment efficacy.

Main Results:

• Disturbed RNA polymerase I transcription in CS cells leads to impaired ribosome function and production of misfolded proteins.
• Elevated ROS in CS cells oxidizes misfolded proteins, triggering a UPR that further represses RNA polymerase I transcription.
• Pharmacological chaperones can disrupt this detrimental feedback loop, restoring proteostasis in CS cells.
• This loss of proteostasis was not observed in mouse models of CS.

Conclusions:

• A novel pathomechanism for Cockayne syndrome involving a feedback loop between RNA polymerase I transcription, translational fidelity, ROS, and UPR is identified.
• Pharmacological chaperones represent a promising therapeutic strategy for Cockayne syndrome by targeting this mechanism.
• Discrepancies between CS patient cells and mouse models highlight the complexity of CS pathogenesis and the need for further investigation.