A new mechanism of arterial calcification in diabetes: interaction between H3K18 lactylation and CHI3L1.

Metabolic changes are an important characteristic of vascular complications in diabetes. The accumulation of lactate in the microenvironment can promote vascular smooth muscle cell (VSMC) calcification in diabetes, although the specific mechanism remains to be fully elucidated. In this study, we explored the characteristics of lactylation in diabetic arterial calcification and the underlying molecular mechanism. We found that in high-glucose calcified VSMC, the overall lactylation level was significantly increased. Mass spectrometry analysis revealed a significant up-regulation of H3 histone lactylation. After site-specific point-mutation at K18 to simulate the delactylation modification, VSMC calcification was significantly reduced. Through a combination of H3K18la ChIP-seq, RNA-seq, H3K18la ChIP-qPCR, and point-mutation experiments, we confirmed that H3K18la can up-regulate CHI3L1. CHI3L1 knockout significantly alleviated VSMC osteogenic phenotype transformation and mouse arterial calcification. RNA-seq analysis of the downstream molecular signaling showed that CHI3L1 activates the IL-13-IL-13Ra2-JAK1-STAT3 pathway. Targeted inhibition of IL-13Ra2 reduced VSMC calcification. We conclude that in a diabetic calcification environment, the H3 histone K18 site undergoes lactylation modification in VSMCs, upregulating CHI3L1, which, in turn, regulates the IL-13-IL-13Ra2-JAK1-STAT3 signaling pathway, ultimately exacerbating arterial calcification. Our study elucidates the epigenetic mechanism by which lactate promotes arterial calcification in diabetes.