Targeting the neuronal calcium sensor DREAM with small-molecules for Huntington's disease treatment

Area of Science:

• Neuroscience
• Molecular Biology
• Pharmacology

Background:

• DREAM (Downstream regulatory element antagonistic modulator) is a neuronal calcium sensor protein involved in Ca2+ and protein homeostasis.
• Reduced DREAM expression or inhibition by repaglinide demonstrates neuroprotection in Huntington's disease (HD) models.
• Existing inhibitors like repaglinide have limitations in potency and duration of action.

Purpose of the Study:

• To identify and develop novel, more potent inhibitors of DREAM for Huntington's disease treatment.
• To validate a newly discovered ligand binding site on DREAM for drug design.
• To investigate the molecular mechanisms of action for novel DREAM inhibitors.

Main Methods:

• Structure-based drug design was employed to identify IQM-PC330.
• In vitro and in vivo cellular and animal models of Huntington's disease were utilized.
• Biochemical assays were performed to assess DREAM binding, gene expression, ion channel modulation, and protein interactions.

Main Results:

• IQM-PC330 was identified as a potent and long-lasting inhibitor of DREAM, outperforming repaglinide.
• A novel ligand binding site on DREAM, involving Tyr118 and Tyr130, was discovered and validated.
• IQM-PC330 demonstrated de-repression of c-fos gene expression, silenced DREAM's effect on K_V4.3 channels, and blocked ATF6/DREAM interaction.

Conclusions:

• DREAM is a validated therapeutic target for Huntington's disease.
• IQM-PC330 represents a more effective molecule for potential HD treatment compared to existing therapies.
• Targeting the novel ligand binding site offers a promising strategy for developing next-generation DREAM inhibitors.