P2Y1 purinergic receptor identified as a diabetes target in a small-molecule screen to reverse circadian β-cell...

Area of Science:

• Chronobiology
• Endocrinology
• Molecular Biology

Background:

• The mammalian circadian clock regulates daily physiological and behavioral rhythms via a transcription feedback loop.
• Disruption of the core clock in pancreatic beta cells leads to impaired hormone exocytosis and hypoinsulinemic diabetes.
• Identifying therapeutic targets for circadian beta-cell failure is crucial for diabetes treatment.

Purpose of the Study:

• To develop a genetically sensitized screen for identifying druggable targets involved in circadian beta-cell dysfunction.
• To discover small molecules that can restore insulin secretion in clock-deficient beta cells.
• To elucidate the molecular mechanisms underlying circadian regulation of insulin secretion.

Main Methods:

• A high-throughput screen using beta cells with a nanoluciferase reporter in the proinsulin polypeptide.
• Screening of 2640 pharmacologically active compounds against CRISPR-Cas9-targeted clock mutant beta cells.
• Validation of hit compounds in primary mouse islets, including electrophysiology and genetic analyses.

Main Results:

• The screen identified insulinotropic molecules that bypass the secretory defect in clock mutant beta cells.
• Ivermectin was identified as a hit compound and validated as a glucose-dependent insulin secretagogue.
• Genetic and pharmacological studies revealed the P2Y1 receptor as a key mediator of ivermectin's insulinotropic effect.

Conclusions:

• The P2Y1 purinergic receptor is a clock-controlled mediator of insulin secretion.
• Ivermectin acts through the P2Y1 receptor to promote insulin release in a glucose-dependent manner.
• The P2Y1 receptor represents a novel therapeutic target for diabetes associated with circadian rhythm disruption.