A BBB-permeable β₃-AR probe enables redox imaging, natural inhibitors discovery, and therapeutic monitoring in glioblastoma.

Abstract

β₃-Adrenergic receptors (β₃-ARs), as a subclass of G protein-coupled receptors (GPCRs), play a pivotal role in regulating oxidative stress. However, the dynamic interplay between their microenvironmental fluctuations and glioma mechanisms remains poorly understood. Here, we report the development of GSHP, a blood-brain barrier (BBB)-permeable probe that simultaneously visualizes β₃-ARs and reversibly monitors the surrounding redox status in real-time. This dual-responsive probe enables reversible dynamic imaging of redox homeostasis around β₃-ARs in living cells under stress conditions, providing direct visual evidence for redox adaptation. Using GSHP for high-throughput screening, we identified and validated baicalin as a potent β₃-AR natural inhibitor that induces glutathione depletion and triggers oxidative stress-mediated apoptosis via the Gα_i/o-extracellular signal-regulated kinase (ERK)-nuclear factor erythroid 2-related factor 2 (Nrf2)-glutamate-cysteine ligase catalytic subunit (GCLc) signaling pathway in U251 glioblastoma cells. In orthotopic U251 glioma mouse models, GSHP penetrated the brain and enabled dual-channel imaging of β₃-AR overexpression and redox imbalance in vivo, allowing for effective glioma discrimination and demonstrating its potential for therapeutic monitoring. GSHP thus serves as a versatile platform for studying β₃-AR-related redox biology and facilitating therapeutic discovery in brain diseases.