HSP90 Inhibition Attenuated Isoflurane-Induced Neurotoxicity in Mice and Human Neuroglioma Cells.

Isoflurane, a widely used inhalation anesthetic in clinical practice, is associated with an increased risk of neuronal injury. Heat shock protein 90 (HSP90) plays a crucial role in maintaining neuronal homeostasis under stress conditions; however, its role during isoflurane exposure remains poorly understood. In this study, we aimed to investigate the protective effects of HSP90 inhibition and explore the regulatory mechanisms underlying these effects during isoflurane exposure. We found that the HSP90 inhibitor 17-N-allylamino-17-demethoxygeldanamycin (17 AAG) has great protective effects in mitigating isoflurane-induced ferroptosis of mouse hippocampus and cultured neuronal cells. We focused on the activity of the crucial protein GPX4 in ferroptosis and found that 17 AAG exerted protective effects, preserving the physiological GPX4 activity under isoflurane exposure; further, 17 AAG restored the protein level of GPX4. Further, we observed that the chaperone-mediated autophagy (CMA) pathway was activated; 17 AAG also mediated GPX4 degradation under isoflurane exposure. Additionally, it interfered with the formation of complexes between HSP90 and Lamp-2a, inhibiting CMA activity, followed by the blockade of GPX4 degradation, further affecting the isoflurane-induced ferroptosis. Based on these findings, we proposed HSP90 inhibition as a protective mechanism against isoflurane-induced ferroptosis in neurons.