Macrophage Phospholipase D3 promotes atherosclerosis via exacerbating foam cell formation and inducing inflammatory responses.

Background: Atherosclerosis is a chronic inflammatory disease and a major cause of global morbidity and mortality. Phospholipase D3 (PLD3) has been reported to be elevated in atherosclerotic plaques, yet its functional role and molecular mechanisms remain unclear. This study investigated the role of PLD3 in atherosclerosis. Methods: Single-cell RNA sequencing of human atherosclerotic tissues was analyzed to define PLD3 expression. Validation was performed in ApoE^-/- mice and THP-1-derived foam cells by qRT-PCR and western blotting. Lentiviral-mediated PLD3 knockdown was followed by oxidized LDL (ox-LDL) stimulation. Lipid accumulation and uptake were assessed by Oil Red O, BODIPY, and DiI-ox-LDL assays, while inflammatory cytokines were quantified by qRT-PCR. RNA sequencing was conducted to explore downstream mechanisms. Results: PLD3 expression was markedly upregulated in atherosclerotic lesions and enriched in plaque macrophages, with diagnostic value confirmed by ROC analysis. In vitro, ox-LDL induced PLD3 upregulation in THP-1 macrophages. PLD3 silencing reduced lipid accumulation and uptake through downregulation of CD36, while concurrently decreasing IL-1β and TNF-α expression. Mechanistically, PLD3 deficiency suppressed NF-κB pathway activation. Conclusion: PLD3 is highly expressed in plaque macrophages and promotes atherosclerosis by enhancing CD36-mediated lipid accumulation and activating NF-κB-driven inflammation. These findings identify PLD3 as a potential therapeutic target for atherosclerotic disease.