RNA switch enabling stress-responsive regulation of protein expression for safer, more consistent gene and mRNA therapies

Unmet Need

Current gene and mRNA therapies lack mechanisms to regulate protein expression in response to intracellular stress. Overexpression of therapeutic proteins can induce ER stress leading to unfolded proteins that do more harm than good, leading to cell apoptosis, inflammation, and suboptimal and variable therapeutic outcomes. There is a need for a gene regulation strategy that enables sustained, therapeutically relevant protein expression while mitigating ER stress and associated immunotoxicity.

Technology

Duke inventors have developed an RNA-based gene expression switch for stress-responsive regulation of therapeutic protein production in gene and mRNA therapies. This switch is intended for incorporation into therapeutic nucleic acid constructs to dynamically modulate protein expression in response to endoplasmic reticulum (ER) stress. Specifically, the system leverages an endogenous feedback loop in which an engineered fragment of X-box binding protein 1 (XBP1F) undergoes splicing by IRE1α endonuclease under ER stress, introducing a frameshift and stop codon upstream of the therapeutic gene to halt further protein production. Once ER stress resolves, new unspliced transcripts restore protein expression, allowing real-time, reversible regulation of expression levels tied to cellular stress. The switch has been validated in mammalian cells using Factor VIII and Leronlimab, demonstrating reduced ER stress markers and effective modulation of protein expression. In a preclinical proof-of-concept study, AAV8-packaged XBP1F-Leronlimab constructs administered intravenously in mice reduced interindividual variability in therapeutic mRNA expression and ER stress marker levels in the liver while maintaining therapeutic protein production.

Other Applications

This technology could also be applied to oncology and Alzheimer’s therapeutics, as well as biologics manufacturing to manage ER stress in high-yield protein production.

Advantages

• Provides real-time, reversible regulation of protein expression in response to ER stress.
• Decreases interindividual variability of therapeutic mRNA expression.
• Enables stress-responsive modulation without requiring external intervention.
• Preserves optimal protein production from delivered genes while minimizing cellular stress, apoptosis, and inflammation.