BRF110, an Orally Active Nurr1-RXRα-Selective Rexinoid, Enhances BDNF Expression without Elevating Triglycerides

Area of Science:

• Neuroscience
• Pharmacology
• Molecular Biology

Background:

• Retinoid X receptor alpha (RXRα) agonists are explored for neurodegenerative diseases.
• Existing RXRα agonists like bexarotene have limitations due to lack of selectivity and side effects.
• Targeting specific RXRα heterodimers offers a potential strategy for improved therapeutic outcomes.

Purpose of the Study:

• To discover and characterize a novel rexinoid with enhanced selectivity for the Nurr1-RXRα heterodimer.
• To improve in vivo stability and brain penetration compared to previous compounds.
• To evaluate the therapeutic potential and safety profile of the novel compound in preclinical models.

Main Methods:

• Structure-activity relationship (SAR) studies and bioactivity evaluations of substituted pyrimidines.
• In vitro assays to confirm heterodimer selectivity.
• In vivo studies in mice to assess brain penetration, neuroprotection against MPP+, and BDNF transcription.
• Biochemical analysis to evaluate triglyceride levels.

Main Results:

• Discovery of BRF110, a brain-penetrant Nurr1-RXRα heterodimer-selective rexinoid.
• BRF110 demonstrated neuroprotective effects against MPP+-induced toxicity in dopaminergic cells.
• BRF110 increased BDNF transcription in mice.
• BRF110 did not elevate triglyceride levels, unlike bexarotene.

Conclusions:

• BRF110 represents a promising therapeutic candidate for Parkinson's disease and potentially other neurodegenerative conditions.
• Heterodimer-selective rexinoids offer a strategy to improve the therapeutic index of RXR-targeting drugs.
• Targeted modulation of RXRα heterodimers can mitigate off-target side effects, overcoming key challenges in rexinoid drug development.