In vivo tracking cystine/glutamate antiporter-mediated cysteine/cystine pool under ferroptosis

Abstract

Cysteine/cystine redox couple plays a vital role in maintaining the cellular redox state of living bio-systems. However, the dynamic changes of the intracellular cysteine/cystine pool mediated by cysteine/glutamate transporter (System X_C^-) in various cellular processes have remained incompletely understood. Here we established a series of strategies around fluorescent probe CP2 for effectively monitoring the intracellular cysteine level in living cells and in vivo zebrafish model, therefore for tracking dynamic changes of system X_C^--mediated cysteine/cystine pool under ferroptosis. Living cell imaging and in vivo visualization both revealed that intracellular cysteine levels could be significantly reduced upon blocking system X_C^- activity and inducing ferroptotic cell death. This kind of blocking was potent against cisplatin-resistant A549R cancer cells, which might bring new potential for treating drug-resistant carcinoma through regulating system X_C^- and processes of ferroptosis. With further improvements in monitoring tools, understanding of system X_C^--mediated cystine/cysteine pool and ferroptosis could certainly offer crucial information in more physiological or pathological processes.

Keywords: Cysteine/glutamate transporter (system X(C)(−)); Ferroptosis; Fluorescent imaging strategy; Intracellular cysteine/cystine pool; Zebrafish.