Rational construction of a novel fluorescent probe for imaging peroxynitrite in the endoplasmic reticulum during drug-induced liver injury

Drug-induced liver injury (DILI) not only poses a serious health threat to patients, but is also a major obstacle to the development of new drugs. The liver toxicity of many drugs is not detected until late in the development process or even after marketing, which significantly increases the cost of new drug development. This may be limited by the lack of tools to detect DILI. Studies have shown that abnormal changes in peroxynitrite (ONOO-) levels in the endoplasmic reticulum of liver cells may be an early manifestation of DILI. Therefore, the development of fluorescent probes to detect ONOO- in the endoplasmic reticulum may provide assistance in the detection of DILI and the screening of new drugs. Herein, we report a fluorescent probe, ER-N, capable of detecting ONOO- in the endoplasmic reticulum with high selectivity and sensitivity. The probe selects di(trifluoromethyl)benzene as the targeting group of the endoplasmic reticulum, which possesses excellent targeting to the endoplasmic reticulum, and provides a new design method for the establishment of other endoplasmic reticulum-targeting probes. In addition, the probe ER-N successfully realized the detection of endogenous and exogenous ONOO- in cells and zebrafish. More importantly, the probe ER-N was able to be used for tracing changes in the levels of ONOO- in the endoplasmic reticulum of cells and tissues under drug stimulation. Together, these results suggest that the probe ER-N has the potential to be a tool for DILI detection and new drug screening.