Macrophages, inflammation, and atherosclerosis.

Area of Science:

• Cardiovascular Biology
• Immunology
• Metabolic Syndrome

Background:

• Macrophages are central to atherogenesis, involved in lipoprotein metabolism, inflammation, and foam cell formation.
• Monocyte chemoattractant protein-1 (MCP-1) and cyclooxygenase-2 (COX-2) are implicated in recruiting monocytes and promoting inflammation in atherosclerosis.
• Foam cell formation results from cholesterol ester accumulation, mediated by scavenger receptors and ACAT-1, and is influenced by cholesterol efflux proteins.

Purpose of the Study:

• To investigate the role of macrophage adipocyte fatty acid-binding protein (aP2) in atherosclerosis development.
• To determine if macrophage aP2's role in atherosclerosis is independent of its function in systemic glucose and lipid metabolism.
• To explore the impact of macrophage aP2 deficiency on inflammatory cytokine production.

Main Methods:

• Utilized low-density lipoprotein receptor (LDLR)-deficient mice.
• Generated mice lacking macrophage-specific aP2 expression (apoE-deficient mice null for macrophage aP2).
• Assessed atherosclerotic lesion development and inflammatory cytokine profiles.

Main Results:

• Macrophage-specific aP2 deficiency significantly reduced atherosclerotic lesion formation in LDLR-deficient mice.
• The protective effect of aP2 deficiency was observed independently of systemic glucose and lipid metabolism.
• Macrophages lacking aP2 exhibited altered inflammatory cytokine production.

Conclusions:

• Macrophage aP2 plays a significant role in promoting atherosclerotic lesion formation.
• This role is independent of aP2's known functions in systemic insulin resistance and obesity.
• Macrophage aP2 influences inflammatory responses and links metabolic syndrome features to atherosclerosis.