ERK5 Activation in Macrophages Promotes Efferocytosis and Inhibits Atherosclerosis
Background—Efferocytosis is a process by which dead and dying cells are removed by phagocytic cells. Efferocytosis by macrophages is thought to curb the progression of atherosclerosis, but the mechanistic insight of this process is lacking.
Methods and Results—When macrophages were fed apoptotic cells (ACs) or treated with pitavastatin in vitro, efferocytosis-related signaling and phagocytic capacity were upregulated in an ERK5 activity-dependent manner. Macrophages isolated from macrophage-specific ERK5 null mice exhibited reduced efferocytosis and levels of gene and protein expression of efferocytosis-related molecules. When these mice were crossed with LDLR-/- mice and fed a high-cholesterol diet, atherosclerotic plaque formation was accelerated, and the plaques had the more advanced and vulnerable morphology.
Conclusions—Our results demonstrate that ERK5, which is robustly activated by statins, is a hub molecule that upregulates macrophage efferocytosis, thereby suppressing atherosclerotic plaque formation. Molecules that upregulate ERK5 and its signaling in macrophages may be good drug targets for suppressing cardiovascular diseases.
- Received August 28, 2013.
- Revision received April 17, 2014.
- Accepted April 22, 2014.