microRNA transport between cells protects from atherosclerosis

Two types of blood vessel cells communicate through small non-coding RNAs to reduce atherosclerosis, reports a paper published in Nature Cell Biology this week. As atherosclerosis is associated with serious health problems, including heart attacks and strokes, these findings could be important in the development of therapeutic strategies. Certain regions of the arteries are protected from atherosclerosis by differences in local blood flow. One such atheroprotective mechanism is mediated by the activity of the transcription factor KLF2, which is found in cells of the blood vessel endothelium—the thin layer of cells that lines the interior surface of blood vessels. Stefanie Dimmeler and colleagues find that KLF2 upregulates expression of the microRNAs miR-143/145 in endothelial cells. They show that when smooth muscle cells, which line the walls of blood vessels, and endothelial cells are cultured together, endothelial cells release small membrane-bound particles, called \\\'microvesicles\\\', containing miR-143/145 that are subsequently taken up by smooth muscle cells. Microvesicle-mediated transport between cells allows endothelial-cell-derived miR-143/145 to regulate the expression of genes in smooth muscle cells. The authors use a mouse model of atherosclerosis to further demonstrate that injection of miR-143/145-containing microvesicles reduces atherosclerotic lesion formation. These findings suggest that the transport of microRNAs between endothelial and smooth muscle cells could be exploited therapeutically to battle atherosclerosis.