Establishment of Neh2-Cre:tdTomato reporter mouse for monitoring the exposure history to electrophilic stress

Cells are often exposed to exogenous and endogenous redox disturbances and exert their protective mechanisms in response to stimuli. The KEAP1-NRF2 system plays pivotal roles in counteracting oxidative damage. Due to the transient nature of NRF2 activation, the identification of cells in which NRF2 is activated in response to systemic stimuli is sometimes not easy. To examine the electrophilic stress response at a single-cell resolution, we aimed to develop a new reporter mouse in this study. A cell-tracing strategy exploiting Cre recombinase-mediated acti-vation of a reporter gene was chosen for stable detection of reporter expression instead of real-time monitoring of the cellular response. We established a transgenic mouse line expressing the Neh2-Cre recombinase fusion protein. As Neh2 is an amino-terminal domain of NRF2 that serves as a degron and mediates KEAP1-dependent degradation and electrophile-inducible stabilization, Neh2-Cre was expected to be activated in response to electrophiles. The Neh2-Cre transgenic mouse was crossed with the ROSA26-loxP-stop-loxP-tdTomato reporter mouse (ROSA-LSL-tdTomato mouse). The compound mutant reporter mice exhibited accumulation of tdTomato-positive cells in various organs after repeated administration of CDDO-Im, one of the NRF2-inducing electro-philes. The mice were also successfully used for the detection of cells that experienced a cisplatin-induced electrophilic stress response.

Automated summary

This study developed a new reporter mouse model to detect cellular response to electrophilic stress. The compound mutant reporter mice showed accumulation of reporter-positive cells in various organs after repeated administration of a specific electrophile and successfully detected cells that experienced a cisplatin-induced electrophilic stress response.