Increasing evidences showed that the survival of macrophages promotes atherogenesis. Macrophage apoptosis in the early phase of atherosclerotic process negatively regulates the progression of atherosclerotic lesions. We demonstrated that a natural anti-oxidant apigenin could ameliorate atherogenesis in ApoE-/- mice. It reduced the number of foam cells and decreased the serum levels of tumor necrosis factor α, interleukin 1β (IL-1β) and IL-6. Our results showed that oxidized low-density lipoprotein (oxLDL) led to the secretion of pro-inflammatory cytokines. Apigenin-induced apoptosis and downregulated the secretion of TNF-α, IL-6 and IL-1β. It is further supported by the use of zVAD, a pan-caspase inhibitor, demonstrating that apigenin lowered cytokine profile through induction of macrophage apoptosis. Moreover, apigenin-induced Atg5/Atg7-dependent autophagy in macrophages pretreated with oxLDL. Results illustrated that autophagy inhibition increased apigenin-induced apoptosis through activation of Bax. The present findings suggest that oxLDL maintained the survival of macrophages and activated the secretion of pro-inflammatory cytokines to initiate atherosclerosis. Apigenin-induced apoptosis of lipid-laden macrophages and resolved inflammation to ameliorate atherosclerosis. In conclusion, combination of apigenin with autophagy inhibition may be a promising strategy to induce foam cell apoptosis and subdue atherogenic cytokines.
Scopus Subject Areas
- Immunology and Allergy
- Oxidized low-density lipoprotein