Dual mechanisms for the antagonistic crosstalk between H3 glycation and H3K4me3 [CUT&Tag]

Cancer cells undergo profound metabolic reprogramming that elevates the intracellular levels of reactive byproducts such as methylglyoxal (MGO), which can non-enzymatically modify macromolecules in a process known as glycation. Histones are particularly susceptible to glycation, resulting in substantial alterations to chromatin structure and the epigenetic landscape. However, the mechanism by which histone glycation alters epigenetic landscape and impacts specific transcriptional output in vivo has remained unclear due to the lack of high-resolution tools. Here, we utilize adduct-, site-, and target-specific antibodies we developed against histone H3 glycation at arginine 17 (H3R17MG-H1), one of the most abundant histone glycation marks, to perform precise detection and enrichment of this mark. With these, we show that H3 glycation preferentially accumulates in euchromatin and directly crosstalks with a key active transcription-associated mark, H3K4me3, at transcription start sites. Mechanistically, H3 glycation antagonizes global H3K4me3 through dual pathways: by preventing the recruitment of WDR5-containing methyltransferase complexes to glycated H3 and by transcriptionally inducing KDM5 demethylases expression. The combined effects lead to genome-wide depletion of H3K4me3 and reprogramming of cellular transcriptional networks. Our findings reveal a distinct role for histone glycation as a potent modulator of epigenetic landscape and transcriptional output, serving as a direct link between altered metabolism and cell fate.