A Gene‐Switch Platform Interfacing with Reactive Oxygen Species Enables Transcription Fine‐Tuning by Soluble and Volatile Pharmacologics and Food Additives

Abstract Synthetic biology aims to engineer transgene switches for precise therapeutic protein control in cell‐based gene therapies. However, off‐the‐shelf trigger‐inducible gene circuits are usually switched on by single or structurally similar molecules. This study presents a mammalian gene‐switch platform that controls therapeutic gene expression by a wide range of molecules generating low, non‐toxic levels of reactive oxygen species (ROS). In this system, KEAP1 (Kelch‐like ECH‐associated protein 1) serves as ROS sensor, regulating the translocation of NRF2 (nuclear factor erythroid 2‐related factor 2) to the nucleus, where NRF2 binds to antioxidant response elements (ARE) to activate the expression of a gene of interest. It is found that a promoter containing eight‐tandem ARE repeats is highly sensitive to the low ROS levels generated by the soluble and volatile molecules, which include food preservatives, food additives, pharmaceuticals, and signal transduction inducers. In a proof‐of‐concept study, it is shown that many of these compounds can independently trigger microencapsulated engineered cells to produce sufficient insulin to restore normoglycemia in experimental type‐1 diabetic mice. It is believed that this system greatly extends the variety of small‐molecule inducers available to drive therapeutic gene switches.