SIRT1 decreases Lox-1-mediated foam cell formation in atherogenesis

Area of Science:

• Cardiovascular Research
• Molecular Biology
• Cellular Metabolism

Background:

• Atherogenesis involves endothelial activation, macrophage infiltration, and foam cell formation.
• Sirtuin 1 (SIRT1), a class III deacetylase, has critical metabolic functions.
• The role of SIRT1 in plaque macrophages and its impact on atherogenesis require further investigation.

Purpose of the Study:

• To analyze the role of SIRT1 in plaque macrophages.
• To determine SIRT1's function in the process of atherogenesis.

Main Methods:

• Utilized partial SIRT1 deletion in atherosclerotic mouse models.
• Investigated peritoneal macrophage behavior in heterozygous SIRT1 mice.
• Performed bone marrow-restricted SIRT1 deletion to confirm macrophage-specific effects.
• Examined the impact of SIRT1 on oxidized low-density lipoprotein (oxLDL) uptake and the NF-κB signaling pathway.

Main Results:

• SIRT1 deletion in macrophages exacerbates atherosclerosis.
• Macrophages from heterozygous SIRT1 mice show increased accumulation of oxLDL, promoting foam cell formation.
• SIRT1 deletion in bone marrow-derived macrophages is sufficient to reduce atherogenesis.
• SIRT1 suppresses oxLDL uptake by downregulating lectin-like oxLDL receptor-1 (Lox-1) expression via NF-κB pathway inhibition.

Conclusions:

• SIRT1 exhibits protective effects against atherosclerosis.
• Reduced macrophage foam cell formation is a key mechanism of SIRT1's protective action.
• Pharmacological activation of SIRT1 presents a potential novel anti-atherosclerotic therapeutic strategy.