Porphyromonas gingivalis infection induces lysine lactylation reprogramming in human umbilical vein endothelial cells

Introduction: (Pg), a keystone periodontal pathogen, is a known risk factor for atherosclerosis and cardiovascular disease. Lysine lactylation (Kla) is an emerging post-translational modification (PTM) that bridges cellular metabolism and epigenetic regulation. However, the involvement of Kla in bacteria-induced endothelial dysfunction remains unexplored. This study aims to characterize the global lactylation landscape in human umbilical vein endothelial cells (HUVECs) following Pg infection. Methods: HUVECs were infected with Pg, and their lactylome was analyzed using LC-MS/MS-based quantitative proteomics. Differentially lactylated sites were identified based on a fold change (FC) of ≥ 1.5 or ≤ 0.67 with a significance level of p < 0.05. Bioinformatics tools, including pathway enrichment and protein-protein interaction (PPI) network analyses, were employed to determine the biological significance of the modified proteins. Results: A total of 5,788 Kla sites were identified across 1,881 proteins. Following Pg infection, 487 sites were significantly upregulated and 598 sites were downregulated. Functional enrichment analysis revealed that differentially lactylated proteins are primarily involved in nucleocytoplasmic transport, bacterial invasion, ribosome biogenesis, and DNA repair mechanisms. Network analysis highlighted five highly interconnected clusters regulating translation, RNA processing, and metabolism. Notably, key endothelial structural and regulatory proteins, including AHNAK (160 sites), MYH9 (56 sites), and FLNA (34 sites), exhibited extensive lactylation. Discussion: This study provides the first comprehensive lactylome profile of Pg-infected HUVECs, identifying lysine lactylation as a novel mechanism linking periodontal infection to endothelial dysfunction. These findings offer a new molecular framework for understanding the pathogenesis of periodontitis-associated cardiovascular diseases and suggest potential biomarkers and therapeutic targets.