In-Depth Profiling of 4‑Hydroxy-2-nonenal Modification via Reversible Thiazolidine Chemistry

Protein modification by lipid-derived electrophiles (LDEs) is associated with various signaling pathways. Among these LDEs, 4-hydroxy-2-nonenal (HNE) is the most toxic, and protein modified with HNE has been linked to various diseases, including Alzheimer’s and Parkinson’s. However, due to their low abundance, in-depth profiling of HNE modifications still presents challenges. This study introduces a novel strategy utilizing reversible thiazolidine chemistry to selectively capture HNE-modified proteins and a palladium-mediated cleavage reaction to release them. Thousands of HNE-modified sites in different cell lines were identified. Combined with ABPP, we discovered a set of HNE-sensitive sites that offer a new tool for studying LDE modifications in proteomes.