High Spatiotemporal Resolution Observation of Glutathione Hydropersulfides in Living Cells and Tissue via a Two-Photon Ratiometric Fluorescent Probe.

Glutathione hydropersulfides (GSSH) are alluded to play crucial roles in signal transduction, redox homeostasis, and metabolic regulation. However, the detailed biological functions of GSSH in these aspects are extremely ambiguous. The key barrier to understand the role of GSSH in biological systems is a lack of detection tools with high spatiotemporal resolution. To address the issues, we are seeking novel chemical tools for GSSH detection. We herein develop the first two-photon ratiometric fluorescent probe (TP-Dise) for GSSH detection with high spatial and temporal resolution in living cells and tissue. On the basis of our probe TP-Dise, we investigate the biosynthesis of GSSH, and the results indicate that GSSH is mainly from two sulfurtransferases, CBS and CSE. Furthermore, we explore the biological function of GSSH in protecting cells from mercury ion-induced cell damage for the first time. The experimental results indicate that mercury ions may induce cell death by causing mitochondrial autophagy. GSSH acts both as antagonist and as antioxidant and can effectively alleviate the damage caused by mercury stress.