Chemoproteomic Profiling of Reactive Cysteines in Response to Oxidative Stress Induced by 6-Hydroxydopamine

Oxidative stress is a well-known driver of neurodegeneration, yet it remains poorly understood how the global cysteine (Cys) proteome is remodeled in such conditions. Proteins with aberrantly modified Cys in response to oxidative stress can induce and exacerbate neurodegeneration. In this study, we induced oxidative stress by treating SH-SY5Y neuronal cells with the neurotoxin 6-hydroxydopamine (6-OHDA). To identify proteins with Cys that had altered oxidation or post-translational modification statuses, we utilized a desthiobiotin iodoacetamide (DBIA) probe, which selectively labels Cys with unmodified and preserved thiols. We identified numerous proteins that exhibited reduced or enhanced Cys reactivity to DBIA in response to 6-OHDA-induced oxidative stress, many of which are critically involved in biological processes linked to cell stress responses (e.g., mitochondrial oxidative stress and apoptosis). Our study defines the remodeling of the Cys proteome and suggests potential Cys-mediated regulatory mechanisms under 6-OHDA-induced oxidative stress conditions. In the context of neurodegeneration and under these conditions, our findings provide a valuable resource for further exploration of the Cys proteome.