Macrophage-Specific E3 Ubiquitin Ligase TRIM31 Reduces Atherosclerotic Plaque Formation by Targeting LOX-1.

BACKGROUND: Atherosclerosis is a chronic inflammatory disease marked by lipid accumulation and immune cell infiltration in arterial walls. Macrophages contribute by internalizing oxidized low-density lipoprotein, forming foam cells, and driving inflammation. The ubiquitin-proteasome system regulates immune and inflammatory responses in atherosclerosis. This study investigated the protective role of TRIM31 (tripartite motif-containing 31), an E3 ubiquitin ligase, in macrophage lipid metabolism and inflammation through selective regulation of LOX-1 (lectin-like oxidized low-density lipoprotein receptor-1). METHODS: Transcriptomic profiling, macrophage-specific RESULTS: TRIM31 was selectively upregulated in macrophages under oxidized low-density lipoprotein stimulation and in atherosclerosis plaques. Trim31 deficiency exacerbated plaque burden, foam cell formation, and inflammatory signaling (n=8 per group). Single-cell analysis revealed enrichment of lipid transport and inflammatory pathways in Trim31-deficient plaques. LOX-1 was identified as a key TRIM31 substrate. TRIM31 promoted K48-linked ubiquitination of LOX-1 at lysine 12, facilitating its degradation. The atheroprotective effects of Trim31 were abolished in CONCLUSIONS: TRIM31, an inducible, macrophage-enriched protective factor in atherosclerosis, restricts foam cell formation and inflammation by targeting LOX-1 for proteasomal degradation. These findings position TRIM31 as a promising therapeutic target for macrophage-driven atherogenesis.