A novel multifunctional fluorescent probe for imaging the regulatory effects of pregnane X receptor on ferroptosis and carboxylesterase in atherosclerosis

Ferroptosis is closely associated with the macrophage foam cells formation during early-stage of atherosclerosis (AS). To date, the effect of ferroptosis-induced inflammatory response on lipid metabolism remains incompletely elucidated. Carboxylesterase (CES) plays an important role in lipid metabolism in macrophages. We speculated from previous reports that during the process of foam cell formation, the reduction in CES activity induced by inflammation leads to excessive lipid accumulation and exacerbates AS. However, it was still unknown whether there was a bidirectional regulation between CES or its agonists and ferroptosis. This was due to the lack of effective tools for simultaneous presentation of intracellular ferroptosis processes and CES levels. To address this situation, we designed a multifunctional fluorescent probe (CAS-FC) to simultaneously detect CES and Fe²⁺, enabling to monitor the interaction between ferroptosis and CES during the early-stage of AS. By employing fluorescence imaging, we confirmed the inhibitory effect of ferroptosis on CES. More significantly, we demonstrate for the first time that pregnane X receptor (PXR), an activator of CES, has a significant anti-ferroptosis effect. These findings are expected to contribute to the development of new strategies for the inhibition of ferroptosis and provide innovative insights into the diagnosis and treatment of AS.