Abstract

Ferroptosis, an iron-dependent form of regulated cell death, has been implicated in the pathogenesis of type 2 diabetes (T2DM), but its underlying mechanisms remain unclear. Here, we identify cystathionine β-synthase (CBS), a rate-limiting enzyme in the trans-sulfuration pathway, as a critical metabolic regulator linking glutathione (GSH) homeostasis to ferroptosis sensitivity in T2DM. Multi-omics integration revealed marked disruption of the ferroptosis pathway and GSH metabolism in patients with T2DM and highlighted CBS as a ferroptosis-associated gene strongly correlated with glycemic traits. Population-level analyses revealed that CBS expression was positively associated with GSH and negatively with plasma ferritin, and Mendelian randomization supported a causal protective effect of CBS on T2DM risk. In vitro, high glucose reduced CBS expression in MIN6 cells, whereas CBS overexpression increased GSH, restored antioxidant capacity, suppressed Fe 2+ accumulation, and shifted ferroptosis markers toward an anti-ferroptotic profile, accompanied by improved β-cell functional gene expression. Notably, inhibition of GSH synthesis largely abolished the protective effects of CBS, indicating that the anti-ferroptotic function is GSH dependent. Mechanistically, cystathionine γ-lyase (CTH) was identified as an essential coregulator of CBS. Disruption of CTH greatly weakened CBS-driven improvements in GSH maintenance, iron–redox homeostasis, and β-cell function, establishing a functional CBS–CTH–GSH axis. In summary, our findings identify that CBS can protect β-cells from ferroptotic injury and functional decline under glucotoxic stress and highlight the CBS–CTH–GSH axis as a promising β-cell-targeted intervention point for delaying or preventing T2DM progression. Graphical Metabolomics and transcriptomics were combined to identify CBS as a key regulator of ferroptosis in T2DM. Multi-dimensional screening and Mendelian randomization established CBS as a molecular hub linki